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  • Detecting duplicate values in a column of a Datatable while traversing through It

    - by Ashish Gupta
    I have a Datatable with Id(guid) and Name(string) columns. I traverse through the data table and run a validation criteria on the Name (say, It should contain only letters and numbers) and then adding the corresponding Id to a List If name passes the validation. Something like below:- List<Guid> validIds=new List<Guid>(); foreach(DataRow row in DataTable1.Rows) { if(IsValid(row["Name"]) { validIds.Add((Guid)row["Id"]); } } In addition to this validation I should also check If the name is not repeating in the whole datatable (even for the case-sensitiveness), If It is repeating, I should not add the corresponding Id in the List. Things I am thinking/have thought about:- 1) I can have another List, check for the "Name" in the same, If It exists, will add the corresponding Guild 2) I cannot use HashSet as that would treat "Test" and "test" as different strings and not duplicates. 3) Take the DataTable to another one where I have the disctict names (this I havent tried and the code might be incorrect, please correct me whereever possible) DataTable dataTableWithDistinctName = new DataTable(); dataTableWithDistinctName.CaseSensitive=true CopiedDataTable=DataTable1.DefaultView.ToTable(true,"Name"); I would loop through the original datatable and check the existence of the "Name" in the CopiedDataTable, If It exists, I wont add the Id to the List. Are there any better and optimum way to achieve the same? I need to always think of performance. Although there are many related questions in SO, I didnt find a problem similar to this. If you could point me to a question similar to this, It would be helpful. Thanks

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  • How to differentiate between to similer fields in Linq Join tables

    - by Azhar
    How to differentiate between to select new fields e.g. Description c.Description and lt.Description DataTable lDt = new DataTable(); try { lDt.Columns.Add(new DataColumn("AreaTypeID", typeof(Int32))); lDt.Columns.Add(new DataColumn("CategoryRef", typeof(Int32))); lDt.Columns.Add(new DataColumn("Description", typeof(String))); lDt.Columns.Add(new DataColumn("CatDescription", typeof(String))); EzEagleDBDataContext lDc = new EzEagleDBDataContext(); var lAreaType = (from lt in lDc.tbl_AreaTypes join c in lDc.tbl_AreaCategories on lt.CategoryRef equals c.CategoryID where lt.AreaTypeID== pTypeId select new { lt.AreaTypeID, lt.Description, lt.CategoryRef, c.Description }).ToArray(); for (int j = 0; j< lAreaType.Count; j++) { DataRow dr = lDt.NewRow(); dr["AreaTypeID"] = lAreaType[j].LandmarkTypeID; dr["CategoryRef"] = lAreaType[j].CategoryRef; dr["Description"] = lAreaType[j].Description; dr["CatDescription"] = lAreaType[j].; lDt.Rows.Add(dr); } } catch (Exception ex) { }

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  • how to use anonymous generic delegate in C# 2.0

    - by matti
    Hi. I have a class called NTree: class NTree<T> { public NTree(T data) { this.data = data; children = new List<NTree<T>>(); _stopTraverse = false; } ... public void Traverse(NTree<T> node, TreeVisitor<T> visitor) { try { _stopTraverse = false; Traverse(node, visitor); } finally { _stopTraverse = false; } } private void TraverseInternal(NTree<T> node, TreeVisitor<T> visitor) { if (_stopTraverse) return; if (!visitor(node.data)) { _stopTraverse = true; } foreach (NTree<T> kid in node.children) Traverse(kid, visitor); } When I try to use Traverse with anonymous delegate I get: Argument '2': cannot convert from 'anonymous method' to 'NisConverter.TreeVisitor' The code: tTable srcTable = new tTable(); DataRow[] rows; rootTree.Traverse(rootTree, delegate(TableRows tr) { if (tr.TableName == srcTable.mappingname) { rows = tr.Rows; return false; } }); This however produces no errors: static bool TableFinder<TableRows>(TableRows tr) { return true; } ... rootTree.Traverse(rootTree, TableFinder); I have tried to put "arrowhead-parenthisis" and everything to anonymous delegate but it just does not work. Please help me! Thanks & BR -Matti

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  • Autocomplet extender control in ajax (asp.net)?

    - by Surya sasidhar
    hi, i am using autocomplete extender in my application but it is not working. this is my code.. <form id="form1" runat="server"> <asp:scriptmanager ID="Scriptmanager1" runat="server"></asp:scriptmanager> <br /> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <div> <cc1:AutoCompleteExtender TargetControlID="TextBox1" MinimumPrefixLength="1" ServiceMethod="GetVideoTitles" CompletionSetCount="10" ServicePath="Myservices.asmx" ID="AutoCompleteExtender1" runat="server"> </cc1:AutoCompleteExtender> </div> </form> this is webservice method public string[] GetVideoTitles(string prefixText) { SqlConnection con = new SqlConnection(@"Data Source=SERVER5\SQLserver2005;Initial Catalog=tpvnew;User ID=xx;Password=525"); con.Open(); SqlCommand cmd = new SqlCommand("video_videotitles", con); cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Add("@prefixText", SqlDbType.VarChar, 50); cmd.Parameters["@prefixText"].Value = prefixText; SqlDataAdapter da = new SqlDataAdapter(cmd); DataTable dt = new DataTable(); da.Fill(dt); string[] items = new string[dt.Rows.Count]; int i = 0; foreach (DataRow dr in dt.Rows) { items.SetValue(dr["videotitle"].ToString(), i); i++; } return items; }

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  • using .NET web service (Dataset) from progress OpenEdge 4GL

    - by jasperdmx
    I created web service in C# .net with input parameter : DataSet in other side, i need to use this web service from progress OpenEdge 4GL 10.1 (not 10.2) the problem is Dataset in OpenEdge cant match with DataSet in .net. always return 0 in the result I'm C# programmer, so dont have deep knowledge in porgress. I did research in progress forum, but not a good result. any help ? thanks in advance. *codes***** //web service : C# .net [webmethod] public int getResult(DataSet ds) { DataTable tbl = ds.Tables["datas"]; int result=0; foreach (DataRow dr in tbl.Rows){ //only 1 record = 1 row result = Convert.toInt32(dr["field1"]); } return result; } //progress OpenEdge 10.1 --- create and fill temp-table : field1 = 30 and only 1 record --- create dataset and bind to temp-table --- connect to web service --- call webmethod : define variable result as integer no-undo. RUN getResult IN hPortType(INPUT dataset,OUTPUT result). message result view-as alert-box info button ok. --- RESULT ALWAYS 0 /****/ anyone know how to "bridge" dataset in progress openedge to .net dataset ? note: this web service works well if called from .net

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  • how I can print WPF treeview items over multiple pages?

    - by RAJKISHOR
    Hello friend, I want to print tree structure showing in WPF treeview control in multiple page. I tried PrintVisual() but it only prints only visible parts. Then I tried FlowDocument and written AddNode(), but its not showing the same result as treeview doimg. Please help me with code. public void AddNodes(int uid, ListItem tSubNode) { string query = "select fullname, id from members where refCode=" + uid + ";"; String memValue; MySqlCommand cmd = new MySqlCommand(query, db.conn); MySqlDataAdapter _DA = new MySqlDataAdapter(cmd); DataTable _DT = new DataTable(); _DA.Fill(_DT); ListOffset += 20; foreach (DataRow _dr in _DT.Rows) { ListItem tNode = new ListItem(); tNode.Margin = new Thickness(ListOffset,0,0,0); memValue = _dr["fullname"].ToString() + " (" + _dr["id"].ToString() + ")"; tNode.Blocks.Add(new Paragraph(new Run(hyp+memValue))); myList.ListItems.Add(tNode); flowDoc.Blocks.Add(myList); _fdrMembers.Document = flowDoc; if (db.HasMembers(Convert.ToInt32(_dr["id"].ToString()))) { AddNodes(Convert.ToInt32(_dr["id"]), tNode); } } ListOffset = 20; } private void button_Click(object sender, RoutedEventArgs e) { ListOffset = 0; myList.ListItems.Clear(); tSuper.Blocks.Clear(); if (db.GetNameByUID(100001) != null) { tSuper.Blocks.Add(new Paragraph(new Run(db.GetNameByUID(100001)))); myList.ListItems.Add(tSuper); AddNodes(100001, tSuper); } MessageBox.Show("Member by ID - "+does.ToString()+", "+dosnt.ToString(), "Error!", MessageBoxButton.OK, MessageBoxImage.Information); }**strong text**

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  • Read StandardOutput Process from BackgroundWorkerProcess method

    - by Nicola Celiento
    Hi all, I'm working with a BackgroundWorker Process from Windows .NET C# application. From the async method I call many instance of cmd.exe Process (foreach), and read from StandardOutput, but at the 3-times cycle the ReadToEnd() method throw Timeout Exception. Here the code: StreamWriter sw = null; DataTable dt2 = null; StringBuilder result = null; Process p = null; for(DataRow dr in dt1.Rows) { arrLine = new string[4]; //new row result = new StringBuilder(); arrLine[0] = dr["ID"].ToString(); arrLine[1] = dr["ChangeSet"].ToString(); #region Initialize Process CMD p = new Process(); ProcessStartInfo info = new ProcessStartInfo(); info.FileName = "cmd.exe"; info.CreateNoWindow = true; info.RedirectStandardInput = true; info.RedirectStandardOutput = true; info.RedirectStandardError = true; info.UseShellExecute = false; p.StartInfo = info; p.Start(); sw = new StreamWriter(p.StandardInput.BaseStream); #endregion using (sw) { if (sw.BaseStream.CanWrite) { sw.WriteLine("cd " + this.path_WORKDIR); sw.WriteLine("tfpt getcs /changeset:" + arrLine[1]); } } string strError = p.StandardError.ReadToEnd(); // Read shell error output commmand (TIMEOUT) result.Append(p.StandardOutput.ReadToEnd()); // Read shell output commmand sw.Close(); sw.Dispose(); p.Close(); p.Dispose(); } Timeout is on code line: string strError = p.StandardError.ReadToEnd(); Can you help me? Thanks!

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  • Strange error when filling a data adapter.

    - by Tim C
    I am receiving the following error in my code (c#, .Net 3.5, VS2008) when I try to connect to an Excel sheet and fill a OleDbDataAdapter with the results of a query. First the error: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. And here is the code, which is honestly pretty simple: var excelFileName = string.Format("c:/Metadata_Tool.xlsm"); var connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0; Data Source={0}; Extended Properties=Excel 12.0;HDR=YES;", excelFileName); var adapter = new OleDbDataAdapter("Select * FROM [Video Tagging XML]", connectionString); var ds = new DataSet(); adapter.Fill(ds, "VTX"); DataTable data = ds.Tables["VTX"]; foreach (DataRow myRow in data.Rows) { foreach (DataColumn myColumn in data.Columns) { Console.Write("\t{0}", myRow[myColumn]); } Console.WriteLine(); } Console.ReadLine(); I get the error on the line adapter.Fill(ds,"VTX");. I did find a microsoft forum post saying to turn on JIT optimization in VS2008 from the Tools/Options/Debug/General menu, but this did not seem to help. Any help would be greatly appreciated thanks!

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  • WPF Toolkit: Nullable object must have a value

    - by Via Lactea
    Hi All, I am trying to create some line charts from a dataset and getting an error (WPF+WPF Toolkit + C#): Nullable object must have a value Here is a code that I use to add some data points to the chart: ObservableCollection points = new ObservableCollection(); foreach (DataRow dr in dc.Tables[0].Rows) { points.Add(new VelChartPoint() { Label = dr[0].ToString(), Value = double.Parse(dr[1].ToString()) }); } Here is a class VelChartPoint public class VelChartPoint : VelObject, INotifyPropertyChanged { public DateTime Date { get; set; } public string Label { get; set; } private double _Value; public double Value { get { return _Value; } set { _Value = value; var handler = PropertyChanged; if (null != handler) { handler.Invoke(this, new PropertyChangedEventArgs("Value")); } } } public string FieldName { get; set; } public event PropertyChangedEventHandler PropertyChanged; public VelChartPoint() { } } So the problem occures in this part of the code points.Add(new VelChartPoint { Name = dc.Tables[0].Rows[0][0].ToString(), Value = double.Parse(dc.Tables[0].Rows[0][1].ToString()) } ); I've made some tests, here are some results i've found out. This part of code does'nt work for me: string[] labels = new string[] { "label1", "label2", "label3" }; foreach (string label in labels) { points.Add(new VelChartPoint { Name = label, Value = 500.0 } ); } But this one works fine: points.Add(new VelChartPoint { Name = "LabelText", Value = double.Parse(dc.Tables[0].Rows[0][1].ToString()) } ); Please, help me to solve this error.

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  • Optimize inserts

    - by ikerib
    Hi! I did an importer in VB .Net witch get data from an SQLServer an inserts this data throught ADSL connection in a remote MySQL server. in the first time, it was like 200 records, but now there are more than 500.000 records and it expends like 11hours exporting all the data and that is bad, veryyy bad. I need to optimize my importer, witch now gets the data into a datatable an them i have a function witch with a loop (row to row) inserts the data with a "insert into" query... like this: For Each dr As DataRow In dt.Rows Console.Write(".") Dim sql As String = "INSERT INTO clientes(id,nombrefis,nombrecom,direccion,codpos,municipio_id,telefono,fax,cif)" & _ "VALUES (@id,@nombrefis,@nombrecom,@direccion,@codpos,@municipio_id,@telefono,@fax,@cif)" cmd = New MySqlCommand(sql, cnn) cmd.Parameters.AddWithValue("id", Int32.Parse(dr("ID EMPRESA").ToString)) cmd.Parameters.AddWithValue("nombrefis", dr("NOMEMP")) cmd.Parameters.AddWithValue("nombrecom", dr("EMPRESA")) cmd.Parameters.AddWithValue("direccion", dr("DIRECC")) cmd.Parameters.AddWithValue("codpos", dr("CODPOS")) cmd.Parameters.AddWithValue("municipio_id", Int32.Parse(dr("CODIGO MUNICIPIO")).ToString) cmd.Parameters.AddWithValue("telefono", dr("TELEF")) cmd.Parameters.AddWithValue("fax", dr("FAX")) cmd.Parameters.AddWithValue("cif", dr("CIF")) cmd.ExecuteNonQuery() Next any ideas or advices? thanks so much

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  • ObjectDataSource.Select with Parameters Time Out

    - by MasterMax1313
    I'm using an ObjectDataSource with a 2008 ReportViewer control and Linq to CSV. The ODS has two parameters (the SQL is spelled out in an XSD file with a table adapter). The Reportviewer takes a very long time to render the output after a button is clicked to generate the report. That's my first problem. Even though it works (most of the time), the processing time worries me, and subsequent requests don't seem to be changing the results shown on the screen. The next issue is that when I go to export the ODS to CSV I'm getting a time out exception on the select method of the ODS (shown below). This works for ODS without parameters, but it seems like now that I've added parameters that it doesn't want to cooperate. I'm fresh out of ideas, any thoughts? <asp:ObjectDataSource ID="obsGetDataAllCustomers" runat="server" SelectMethod="GetDataAllCustomers" TypeName="my.myAdapter.AllCustomers" OldValuesParameterFormatString="original_{0}" > <SelectParameters> <asp:ControlParameter ControlID="StartDate" Name="Start" PropertyName="Text" Type="DateTime" /> <asp:ControlParameter ControlID="EndDate" Name="_End" PropertyName="Text" Type="DateTime" /> </SelectParameters> </asp:ObjectDataSource> After button click to view report - rvAllCustomers.LocalReport.Refresh() Export to CSV (adding the items returned to a list which is then processed by working code) - For Each dr As DataRow In CType(obs.Select(), DataView).Table.Rows l.Add(New FullOrderOutput(dr)) Next

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  • reading dbase file without standard .dbf extension.

    - by Nathan W
    I am trying to read a file which is just a dbase file but without the standard extension the file is something like: Test.Dat I am using this block of code to try and read the file: string ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=C:\Temp;Extended Properties=dBase III"; OleDbConnection dBaseConnection = new OleDbConnection(ConnectionString); dBaseConnection.Open(); OleDbDataAdapter oDataAdapter = new OleDbDataAdapter("SELECT * FROM Test", ConnectionString); DataSet oDataSet = new DataSet(); oDataAdapter.Fill(oDataSet);//I get the error right here... DataTable oDataTable = oDataSet.Tables[0]; foreach (DataRow dr in oDataTable.Rows) { Console.WriteLine(dr["Name"]); } Of course this crashes because it can't find the dbase file called test, but if I rename the file to Test.dbf it works fine. I can't really rename the file all the time because a third party application uses it as its file format. Does anyone know a way to read a dbase file without a standard extension in C#. Thanks.

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  • Getting minimum - Min() - for DateTime column in a DataTable using LINQ to DataSets?

    - by Jay Stevens
    I need to get the minimum DateTime value of a column in a DataTable. The DataTable is generated dynamically from a CSV file, therefore I don't know the name of that column until runtime. Here is code I've got that doesn't work... private DateTime GetStartDateFromCSV(string inputFile, string date_attr) { EnumerableRowCollection<DataRow> table = CsvStreamReader.GetDataTableFromCSV(inputFile, "input", true).AsEnumerable(); DateTime dt = table.Select(record => record.Field<DateTime>(date_attr)).Min(); return dt; } The variable table is broken out just for clarity. I basically need to find the minimum value as a DateTime for one of the columns (to be chosen at runtime and represented by date_attr). I have tried several solutions from SO (most deal with known columns and/or non-DateTime fields). What I've got throws an error at runtime telling me that it can't do the DateTime conversion (that seems to be a problem with Linq?) I've confirmed that the data for the column name that is in the string date_attr is a date value.

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  • Procedure or function AppendDataCT has too many arguments specified

    - by salvationishere
    I am developing a C# VS 2008 / SQL Server website application. I am a newbie to ASP.NET. I am getting the above compiler error. Can you give me advice on how to fix this? Code snippet: public static string AppendDataCT(DataTable dt, Dictionary<int, string> dic) { string connString = ConfigurationManager.ConnectionStrings["AW3_string"].ConnectionString; string errorMsg; try { SqlConnection conn2 = new SqlConnection(connString); SqlCommand cmd = conn2.CreateCommand(); cmd.CommandText = "dbo.AppendDataCT"; cmd.CommandType = CommandType.StoredProcedure; cmd.Connection = conn2; SqlParameter p1, p2, p3; foreach (string s in dt.Rows[1].ItemArray) { DataRow dr = dt.Rows[1]; // second row p1 = cmd.Parameters.AddWithValue((string)dic[0], (string)dr[0]); p1.SqlDbType = SqlDbType.VarChar; p2 = cmd.Parameters.AddWithValue((string)dic[1], (string)dr[1]); p2.SqlDbType = SqlDbType.VarChar; p3 = cmd.Parameters.AddWithValue((string)dic[2], (string)dr[2]); p3.SqlDbType = SqlDbType.VarChar; } conn2.Open(); cmd.ExecuteNonQuery(); It errors on this last line here. And here is that SP: ALTER PROCEDURE [dbo].[AppendDataCT] @col1 VARCHAR(50), @col2 VARCHAR(50), @col3 VARCHAR(50) AS BEGIN SET NOCOUNT ON; DECLARE @TEMP DATETIME SET @TEMP = (SELECT CONVERT (DATETIME, @col3)) INSERT INTO Person.ContactType (Name, ModifiedDate) VALUES( @col2, @TEMP) END

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  • Unit Testing Error - The unit test adapter failed to connect to the data source or to read the data

    - by michael.lukatchik
    I'm using VSTS 2K8 and I've set up a Unit Test Project. In it, I have a test class with a method that does a simple assertion. I'm using an Excel 2007 spreadsheet as my data source. My test method looks like this: [DataSource("System.Data.Odbc", "Dsn=Excel Files;dbq=|DataDirectory|\\MyTestData.xlsx;defaultdir=C:\\TestData;driverid=1046;maxbuffersize=2048;pagetimeout=5", "Sheet1", DataAccessMethod.Sequential)] [DeploymentItem("MyTestData.xlsx")] [TestMethod()] public void State_Value_Is_Set() { string expected = "MD"; string actual = TestContext.DataRow["State"] as string; Assert.AreEqual(expected, actual); } As indicated in the method decoration attributes, my Excel spreadsheet is on my local C:/ Drive. In it, the sheet where all of my data is located is named "Sheet1". I've copied the Excel spreadsheet into my project and I've set its Build Action = "Content" and I've set its Copy to Output Directory = "Copy if Newer". When trying to run this simple unit test, I receive the following error: The unit test adapter failed to connect to the data source or to read the data. For more information on troubleshooting this error, see "Troubleshooting Data-Driven Unit Tests" (http://go.microsoft.com/fwlink/?LinkId=62412) in the MSDN Library. Error details: ERROR [42S02] [Microsoft][ODBC Excel Driver] The Microsoft Office Access database engine could not find the object 'Sheet1'. Make sure the object exists and that you spell its name and the path name correctly. I've verified that the sheet name is spelled correctly (i.e. Sheet1) and I've verified that my data sources are set correctly. Web searches haven't turned up much at all. And I'm totally stumped. All help or input is appreciated!!!!

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  • Need help in tuning a sql-query

    - by Viper
    Hello, i need some help to boost this SQL-Statement. The execution time is around 125ms. During the runtime of my program this sql (better: equally structured sqls for different tables) will be called 300.000 times. The average row count in the tables lies around 10.000.000 rows and new rows (updates/inserts) will be added with a timestamp each day. Data which are interesting for this particular export-program lies in the last 1-3 days. Maybe this is helpful for an index to create. The data i need is the current valid row for a given id and the forerunner datarow to get the updates (if exists). We use a Oracle 11g database and Dot.Net Framework 3.5 SQL-Statement to boost: select ID_SOMETHING, -- Number(12) ID_CONTRIBUTOR, -- Char(4 Byte) DATE_VALID_FROM, -- DATE DATE_VALID_TO -- DATE from TBL_SOMETHING XID where ID_SOMETHING = :ID_INSTRUMENT and ID_CONTRIBUTOR = :ID_CONTRIBUTOR and DATE_VALID_FROM <= :EXPORT_DATE and DATE_VALID_TO >= :EXPORT_DATE order by DATE_VALID_FROM asc; Here i uploaded the current Explain-Plan for this query. I'm not a database expert so i don't know which index-type would fit best for this requirement. I have seen that there are many different possible index-types which could be applied. Maybe Oracle Optimizer Hints are helpful, too. Does anyone has a good idea for tuning this sql or can point me in a right direction?

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  • C# and SQL - sub select from a table parameter

    - by Dr.HappyPants
    Below is a code snippet for passing a table as a parameter to a query that can be used in Sql Server 2008. I'm confused though about the "SELECT id.custid FROM @custids id". Why does it use id.custid and @custids id...? private static void datatable_example() { string [] custids = {"ALFKI", "BONAP", "CACTU", "FRANK"}; DataTable custid_list = new DataTable(); custid_list.Columns.Add("custid", typeof(String)); foreach (string custid in custids) { DataRow dr = custid_list.NewRow(); dr["custid"] = custid; custid_list.Rows.Add(dr); } using(SqlConnection cn = setup_connection()) { using(SqlCommand cmd = cn.CreateCommand()) { cmd.CommandText = @"SELECT C.CustomerID, C.CompanyName FROM Northwind.dbo.Customers C WHERE C.CustomerID IN (SELECT id.custid FROM @custids id)"; cmd.CommandType = CommandType.Text; cmd.Parameters.Add("@custids", SqlDbType.Structured); cmd.Parameters["@custids"].Direction = ParameterDirection.Input; cmd.Parameters["@custids"].TypeName = "custid_list_tbltype"; cmd.Parameters["@custids"].Value = custid_list; using (SqlDataAdapter da = new SqlDataAdapter(cmd)) using (DataSet ds = new DataSet()) { da.Fill(ds); PrintDataSet(ds); } } }

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  • Most efficient way to check for DBNull and then assign to a variable?

    - by ilitirit
    This question comes up occasionally but I haven't seen a satisfactory answer. A typical pattern is (row is a DataRow): if (row["value"] != DBNull.Value) { someObject.Member = row["value"]; } My first question is which is more efficient (I've flipped the condition): row["value"] == DBNull.Value; // Or row["value"] is DBNull; // Or row["value"].GetType() == typeof(DBNull) // Or... any suggestions? This indicates that .GetType() should be faster, but maybe the compiler knows a few tricks I don't? Second question, is it worth caching the value of row["value"] or does the compiler optimize the indexer away anyway? eg. object valueHolder; if (DBNull.Value == (valueHolder = row["value"])) {} Disclaimers: row["value"] exists. I don't know the column index of the column (hence the column name lookup) I'm asking specifically about checking for DBNull and then assignment (not about premature optimization etc). Edit: I benchmarked a few scenarios (time in seconds, 10000000 trials): row["value"] == DBNull.Value: 00:00:01.5478995 row["value"] is DBNull: 00:00:01.6306578 row["value"].GetType() == typeof(DBNull): 00:00:02.0138757 Object.ReferenceEquals has the same performance as "==" The most interesting result? If you mismatch the name of the column by case (eg. "Value" instead of "value", it takes roughly ten times longer (for a string): row["Value"] == DBNull.Value: 00:00:12.2792374 The moral of the story seems to be that if you can't look up a column by it's index, then ensure that the column name you feed to the indexer matches the DataColumn's name exactly. Caching the value also appears to be nearly twice as fast: No Caching: 00:00:03.0996622 With Caching: 00:00:01.5659920 So the most efficient method seems to be: object temp; string variable; if (DBNull.Value != (temp = row["value"]) { variable = temp.ToString(); } This was a good learning experience.

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  • How to differentiate between two similar fields in Linq Join tables

    - by Azhar
    How to differentiate between two select new fields e.g. Description c.Description and lt.Description DataTable lDt = new DataTable(); try { lDt.Columns.Add(new DataColumn("AreaTypeID", typeof(Int32))); lDt.Columns.Add(new DataColumn("CategoryRef", typeof(Int32))); lDt.Columns.Add(new DataColumn("Description", typeof(String))); lDt.Columns.Add(new DataColumn("CatDescription", typeof(String))); EzEagleDBDataContext lDc = new EzEagleDBDataContext(); var lAreaType = (from lt in lDc.tbl_AreaTypes join c in lDc.tbl_AreaCategories on lt.CategoryRef equals c.CategoryID where lt.AreaTypeID== pTypeId select new { lt.AreaTypeID, lt.Description, lt.CategoryRef, c.Description }).ToArray(); for (int j = 0; j< lAreaType.Count; j++) { DataRow dr = lDt.NewRow(); dr["AreaTypeID"] = lAreaType[j].LandmarkTypeID; dr["CategoryRef"] = lAreaType[j].CategoryRef; dr["Description"] = lAreaType[j].Description; dr["CatDescription"] = lAreaType[j].; lDt.Rows.Add(dr); } } catch (Exception ex) { }

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  • DataTable won't DataBind with a DataTable.NewRow()

    - by David
    Is DataRow.NewRow() insufficient as the only row in a DataTable? I would expect this to work, but it doesn't. It's near the end of my Page_Load inside my If(!Postback) block. gridCPCP is GridView DataTable dt = new DataTable(); dt.Columns.Add("ID", int.MinValue.GetType()); dt.Columns.Add("Code", string.Empty.GetType()); dt.Columns.Add("Date", DateTime.MinValue.GetType()); dt.Columns.Add("Date2", DateTime.MinValue.GetType()); dt.Columns.Add("Filename", string.Empty.GetType()); //code to add rows if (dt.Rows.Count > 0) { gridCPCP.DataSource = dt; gridCPCP.DataBind(); } else { dt.Rows.Add(dt.NewRow()); gridCPCP.DataSource = dt; gridCPCP.DataBind(); //EXCEPTION int TotalColumns = gridCPCP.Rows[0].Cells.Count; gridCPCP.Rows[0].Cells.Clear(); gridCPCP.Rows[0].Cells.Add(new TableCell()); gridCPCP.Rows[0].Cells[0].ColumnSpan = TotalColumns; gridCPCP.Rows[0].Cells[0].Text = "No Record Found"; } The exception throws on gridCPCP.DataBind() and only when execution reaches the else block. If there were rows added above via dt.Rows.Add(new object[] { ... } binding works. System.ArgumentOutOfRangeException: Length cannot be less than zero. Parameter name: length

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  • desing pattern for related inputs

    - by curiousMo
    My question is a design question : let's say i have a data entry web page with 4 drop down lists, each depending on the previous one, and a bunch of text boxes. country (ddl), state (ddl), city (ddl), boro (ddl), address (txtBox), zipcode(txtbox). and an object that represents a datarow with a value for each. naturally the country, state, city and boro values will be values of primary keys of some lookup tables. when the user chooses to edits that record, i would load it from database and load it into the page. the issue that I have is how to streamline loading the ddls. i have some code that would grab the object, look thru its values and move them to their corresponding input controls in one shot. but in this case i will have to load possible values of country, then assign values, then load values of state, then assign value ans so on. I guess i am looking for an elegant solution. i am using asp.net, but i think it is irrelevant to the question. i am looking more into a design pattern. thanks

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  • Can I programmatically add a linkbutton to gridview?

    - by pschorf
    I've been looking through some similar questions without any luck. What I'd like to do is have a gridview which for certain items shows a linkbutton and for other items shows a hyperlink. This is the code I currently have: public void gv_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow) { var data = (FileDirectoryInfo)e.Row.DataItem; var img = new System.Web.UI.HtmlControls.HtmlImage(); if (data.Length == null) { img.Src = "/images/folder.jpg"; var lnk = new LinkButton(); lnk.ID = "lnkFolder"; lnk.Text = data.Name; lnk.Command += new CommandEventHandler(changeFolder_OnCommand); lnk.CommandArgument = data.Name; e.Row.Cells[0].Controls.Add(lnk); } else { var lnk = new HyperLink(); lnk.Text = data.Name; lnk.Target = "_blank"; lnk.NavigateUrl = getLink(data.Name); e.Row.Cells[0].Controls.Add(lnk); img.Src = "/images/file.jpg"; } e.Row.Cells[0].Controls.AddAt(0, img); } } where the first cell is a TemplateField. Currently, everything displays correctly, but the linkbuttons don't raise the Command event handler, and all of the controls disappear on postback. Any ideas?

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  • how to bind the converted value from a datatable to my gridview.

    - by Ranjana
    how to bind the value to gridview i have a datatable DataTable dtBindGrid = new DataTable(); dtBindGrid = serviceobj.SelectExamTimeTable(txtSchoolName.Text, txtBranchName.Text, txtClass.Text, txtExamName.Text); foreach (DataRow row in dtBindGrid.Rows) { strgetday= row["Day"].ToString(); strgetdate = row["Date"].ToString(); DatedTime = Convert.ToDateTime(row["Time"].ToString()); strgettime = DatedTime.ToString("t"); strgetsubject = row["Subject"].ToString(); strgetduration = row["Duration"].ToString(); strgetsession = row["Session"].ToString(); strgetminmark = row["MinMarks"].ToString(); strgetmaxmark = row["MaxMarks"].ToString(); // dtBindGrid.Rows.Add(row); } GrdExamTimeTable.DataSource = dtBindGrid.DefaultView; GrdExamTimeTable.DataBind(); this datatable will return me some values like day,date,time,duration,subject,.. here im getting each value in string bec to convert the Time as 9.00am or 9.00pm DatedTime = Convert.ToDateTime(row["Time"].ToString()); strgettime = DatedTime.ToString("t"); .... how to bind this converted value to my gridview.

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  • System.InvalidOperationException with SQlBulkCopy

    - by Pandiya Chendur
    I got the following error when executing bulkcopy. System.InvalidOperationException The given value of type String from the data source cannot be converted to type decimal of the specified target column. I use the following code. DataTable empTable = DataTemplate.GetEmployees(); DataRow row; for (int i = 0; i < gv.Rows.Count;i++ ) { row = empTable.NewRow(); string empName = gv.DataKeys[i].Values[0].ToString(); //first key string hourSalary = gv.DataKeys[i].Values[1].ToString(); //second key row["Emp_Name"] = empName; row["Hour_Salary"] = Convert.ToDecimal(hourSalary); row["Advance_amount"] = Convert.ToDecimal(0); row["Created_Date"] = Convert.ToDateTime(System.DateTime.Now.ToString()); row["Created_By"] = Convert.ToInt64(1); row["Is_Deleted"] = Convert.ToInt64(0); empTable.Rows.Add(row); } InsertintoEmployees(empTable, "Employee"); My SQL datatypes for the above fields are: Emp_Name nvarchar(50) , Hour_Salary numeric(18, 2), Advance_amount numeric(18, 2), Created_Date datetime, Created_By numeric(18, 0), Is_Deleted numeric(18, 0) I don't know what I am doing wrong.

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  • CommandBuilder and SqlTransaction to insert/update a row

    - by Jesse
    I can get this to work, but I feel as though I'm not doing it properly. The first time this runs, it works as intended, and a new row is inserted where "thisField" contains "doesntExist" However, if I run it a subsequent time, I get a run-time error that I can't insert a duplicate key as it violate the primary key "thisField". static void Main(string[] args) { using(var sqlConn = new SqlConnection(connString) ) { sqlConn.Open(); var dt = new DataTable(); var sqlda = new SqlDataAdapter("SELECT * FROM table WHERE thisField ='doesntExist'", sqlConn); sqlda.Fill(dt); DataRow dr = dt.NewRow(); dr["thisField"] = "doesntExist"; //Primary key dt.Rows.Add(dr); //dt.AcceptChanges(); //I thought this may fix the problem. It didn't. var sqlTrans = sqlConn.BeginTransaction(); try { sqlda.SelectCommand = new SqlCommand("SELECT * FROM table WITH (HOLDLOCK, ROWLOCK) WHERE thisField = 'doesntExist'", sqlConn, sqlTrans); SqlCommandBuilder sqlCb = new SqlCommandBuilder(sqlda); sqlda.InsertCommand = sqlCb.GetInsertCommand(); sqlda.InsertCommand.Transaction = sqlTrans; sqlda.DeleteCommand = sqlCb.GetDeleteCommand(); sqlda.DeleteCommand.Transaction = sqlTrans; sqlda.UpdateCommand = sqlCb.GetUpdateCommand(); sqlda.UpdateCommand.Transaction = sqlTrans; sqlda.Update(dt); sqlTrans.Commit(); } catch (Exception) { //... } } } Even when I can get that working through trial and error of moving AcceptChanges around, or encapsulating changes within Begin/EndEdit, then I begin to experience a "Concurrency violation" in which it won't update the changes, but rather tell me it failed to update 0 of 1 affected rows. Is there something crazy obvious I'm missing?

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