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• How should I lock the table in this VB6 / Access application?

  - by Brian Hooper

  I'm working on a VB6 application using an Access database. The application writes messages to a log table from time to time. Several instances of the application may be running simultaneously and to distinguish them they each have their own run number. The run number is deduced from the log table thus... Set record_set = New ADODB.Recordset query_string = "SELECT MAX(RUN_NUMBER) + 1 AS NEW_RUN_NUMBER FROM ERROR_LOG" record_set.CursorLocation = adUseClient record_set.Open query_string, database_connection, adOpenStatic, , adCmdText record_set.MoveLast If IsNull(record_set.Fields("NEW_RUN_NUMBER")) Then run_number = 0 Else run_number = record_set.Fields("NEW_RUN_NUMBER") End If command_string = "INSERT INTO ERROR_LOG (RUN_NUMBER, SEVERITY, MESSAGE) " & _ " VALUES (" & Str$(run_number) & ", " & _ " " & Str$(SEVERITY_INFORMATION) & ", " & _ " 'Run Started'); " database_connection.Execute command_string Obviously there is a small gap between the calculation of the run number and the appearance of the new row in the database, and to prevent another instance getting access between the two operations I'd like to lock the table; something along the lines of SET TRANSACTION READ WRITE RESERVING ERROR_LOG FOR PROTECTED WRITE; How should I go about doing this? Would locking the recordset do any good (the row in the record set doesn't match any particular row in the database)?

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• Should constant contructor aguments be passed by reference or value?

  - by Mike

  When const values are passed to an object construct should they be passed by reference or value? If you pass by value and the arguments are immediately fed to initializes are two copies being made? Is this something that the compiler will automatically take care of. I have noticed that all textbook examples of constructors and intitializers pass by value but this seems inefficient to me. class Point { public: int x; int y; Point(const int _x, const int _y) : x(_x), y(_y) {} }; int main() { const int a = 1, b = 2; Point p(a,b); Point q(3,5); cout << p.x << "," << p.y << endl; cout << q.x << "," << q.y << endl; } vs. class Point { public: int x; int y; Point(const int& _x, const int& _y) : x(_x), y(_y) {} }; Both compile and do the same thing but which is correct?

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• Inline form editing on client side

  - by bykasif

  I see some web sites use dynamic forms(I am not sure about how to call them!) to edit a group of data. For example: there is a group of data such as name, last name, city, country.etc. when user clicks on EDIT button, instead of doing postback, a form, consisisting of 2 textboxes + 2 comboboxes, dynamically opens to edit,And then when you click on Save button, edit form disappears, and all data updates.. Now, I know what happens over here is using Ajax for server calls and some javascript for dom manipulation.. I even found some jquery plugins for textbox editing.. However, I could not found anything for full implementation of form fields. Therefore I have implemented it on asp.net by jquery ajax calls and dom manipulation manually. here is my process: 1) when Edit button clicked: Make a ajax call to server to retrieve necessary formedit.aspx 2) it returns editable form fields with values assigned. 3) when Save button clicked: make ajax call to server to retrieve formupdateprocess.aspx page. it basically do the database updates and then return necessary DOM snipplet (...) to insert current page.. well it works but MY PROBLEM, is performance.. Result seems slower than samples I see in other sites.:(( IS there anything that I dont know? a better way to implement this??

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• How to render all records from a nested set into a real html tree

  - by Christoph Schiessl

  I'm using the awesome_nested_set plugin in my Rails project. I have two models that look like this (simplified): class Customer < ActiveRecord::Base has_many :categories end class Category < ActiveRecord::Base belongs_to :customer # Columns in the categories table: lft, rgt and parent_id acts_as_nested_set :scope => :customer_id validates_presence_of :name # Further validations... end The tree in the database is constructed as expected. All the values of parent_id, lft and rgt are correct. The tree has multiple root nodes (which is of course allowed in awesome_nested_set). Now, I want to render all categories of a given customer in a correctly sorted tree like structure: for example nested <ul> tags. This wouldn't be too difficult but I need it to be efficient (the less sql queries the better). Update: Figured out that it is possible to calculate the number of children for any given Node in the tree without further SQL queries: number_of_children = (node.rgt - node.lft - 1)/2. This doesn't solve the problem but it may prove to be helpful.

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• Pass List of models to controller ASP.NET MVC 5

  - by user3697231

  I have a view where user can enter some data. But problem is this: Let's say you have 3 text box on view. Every time user can fill multiple times this 3 text boxes. To clarify, let's say user fills this 3 text boxes and press button which adds on form again these 3 text boxes. Now when user clicks submit this form is sent to controller, but how do I sent List of models as parameter. My architecture for this problem is something like this: MyModel public int ID { get;set; } public string Something { get; set; } /*This three textboxes can user set multiple times*/ /*Perhaps i Can create new model with these properties and then /*put List of that model as property here, but how to fill that list inside view ??*/ public string TextBoxOneValue { get; set; } public string TextBoxTwoValue { get; set; } public string TextBoxThreeValue { get; set; } Now, i was thinking that i Create PartialView with this 3 text boxes, and then when user clicks button on view another PartialView is loaded. And now, let's say I have Two partial views loaded, and user clicks submit, how that I pass list with values of these 3 text boxes to controller ??

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• jQuery + form + textinput > Is it possible to display one value in a textinput and submit another?

  - by Ivan Kruchkoff

  I'm working on an application where dates are passed as yyyy-mm-dd but displayed to the client as mm-dd-yyyy (US based client). I'm using a jQuery datepicker for selecting from/to dates in a report and would like to show the dates to the client as mm-dd-yyyy but when the form is submitted, submit as yyyy-mm-dd. Is it possible to display one value in a textinput textbox and have another submitted without needing to hook into onSubmit? I've come up with the following alternatives: Hide the text input for the from and to fields, create dummy fields and make use of the following jQuery date picker functions: altField and altFormat to display the value to the client in their preferred way and deal only with the submitted values which are set through the alt functions. Have an onSubmit javascript call to change the dates from mm-dd-yyyy to dd-mm-yyyy and also change the value=" to change the date to the client's preferred format. Rewrite the app to handle all dates in mm-dd-yyyy and hope the client never has non-US customers that would like their dates in a specific format. Change all dates to dd-Mon-YYYY e.g. 26-May-2010 as all of our client's customers are guaranteed to be English only.

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• C++ union data-structure, easy acccess of bits within a DWORD

  - by TK

  Im running through a set of DirectX tutorials online and I have the following structure: struct CUSTOMVERTEX { FLOAT x, y, z, rhw; // from the D3DFVF_XYZRHW flag DWORD color; // from the D3DFVF_DIFFUSE flag } My basic understanding of directX leads me to thing tha color is made up of 8-bit alpha, red, green and blue channels. I am attempting to get east access to these channels. Rather than write the following code numerous times (within the CUSTOMVERTEX structure): public: int red() { return (color & 0x00FF0000) >> 16; } I could write a more elegant somution with a combination of a union and a structure e.g. struct CUSTOMVERTEX { FLOAT x, y, z, rhw; // from the D3DFVF_XYZRHW flag #pragma pack(2) union { DWORD color; // from the D3DFVF_DIFFUSE flag struct { char a; char r; char g; char b; }; }; } However this does not appear to function as expected, the values in r, g, & b almost appear the reverse of whats in color e.g. if color is 0x12345678 a = 0x78, r = 0x56. Is this an endieness issue? Also what other problems could I be expecting from this solution? e.g. overflow from the color members? I guess what Im asking is ... is there a better way to do this?!

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• java hashmap array to double array

  - by Tweety

  Hi, I declared LinkedHashMap<String, float[]> and now I want to convert float[] values into double[][]. I am using following code. LinkedHashMap<String, float[]> fData; double data[][] = null; Iterator<String> iter = fData.keySet().iterator(); int i = 0; while (iter.hasNext()) { faName = iter.next(); tValue = fData.get(faName); //data = new double[fData.size()][tValue.length]; for (int j = 0; j < tValue.length; j++) { data[i][j] = tValue[j]; } i++; } When I try to print data System.out.println(Arrays.deepToString(data)); it doesn't show the data :( I tried to debug my code and i figured out that I have to initialize data outside the while loop but then I don't know the array dimensions :( How to solve it? Thanks

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• WPF Binding Path=/ not working?

  - by Mark

  I've set up my DataContext like this: <Window.DataContext> <c:DownloadManager /> </Window.DataContext> Where DownloadManager is Enumerable<DownloadItem>. Then I set my DataGrid like this: <DataGrid Name="dataGrid1" ItemsSource="{Binding Path=/}" ... So that it should list all the DownloadItems, right? So I should be able to set my columns like: <DataGridTextColumn Binding="{Binding Path=Uri, Mode=OneWay}" Where Uri is a property of the DownloadItem. But it doesn't seem to like this. In the visual property editor, it doesn't recognize Uri is a valid property, so I'm guessing I'm doing something wrong. It was working before, when I had the data grid binding to Values, but then I took that enumerable out of the DownloadManager and made itself enumerable. How do I fix this? PS: By "doesn't work" I mean it doesn't list any items. I've added some to the constructor of the DM, so it shouldn't be empty.

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• Ruby 1.9: turn these 4 arrays into hash of key/value pairs

  - by randombits

  I have four arrays that are coming in from the client. Let's say that there is an array of names, birth dates, favorite color and location. The idea is I want a hash later where each name will have a hash with respective attributes: Example date coming from the client: [name0, name1, name2, name3] [loc0, loc1] [favcololor0, favcolor1] [bd0, bd1, bd2, bd3, bd4, bd5] Output I'd like to achieve: name0 => { location => loc0, favcolor => favcolor0, bd => bd0 } name1 => { location => loc1, favcolor => favcolor1, bd => bd1 } name2 => { location => nil, favcolor => nil, bd => bd2 } name3 => { location => nil, favcolor => nil, bd => bd3 } I want to have an array at the end of the day where I can iterate and work on each particular person hash. There need not be an equivalent number of values in each array. Meaning, names are required.. and I might receive 5 of them, but I only might receive 3 birth dates, 2 favorite colors and 1 location. Every missing value will result in a nil. How does one make that kind of data structure with Ruby 1.9?

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• C++ Virtual Methods for Class-Specific Attributes or External Structure

  - by acanaday

  I have a set of classes which are all derived from a common base class. I want to use these classes polymorphically. The interface defines a set of getter methods whose return values are constant across a given derived class, but vary from one derived class to another. e.g.: enum AVal { A_VAL_ONE, A_VAL_TWO, A_VAL_THREE }; enum BVal { B_VAL_ONE, B_VAL_TWO, B_VAL_THREE }; class Base { //... virtual AVal getAVal() const = 0; virtual BVal getBVal() const = 0; //... }; class One : public Base { //... AVal getAVal() const { return A_VAL_ONE }; BVal getBVal() const { return B_VAL_ONE }; //... }; class Two : public Base { //... AVal getAVal() const { return A_VAL_TWO }; BVal getBVal() const { return B_VAL_TWO }; //... }; etc. Is this a common way of doing things? If performance is an important consideration, would I be better off pulling the attributes out into an external structure, e.g.: struct Vals { AVal a_val; VBal b_val; }; storing a Vals* in each instance, and rewriting Base as follows? class Base { //... public: AVal getAVal() const { return _vals->a_val; }; BVal getBVal() const { return _vals->b_val; }; //... private: Vals* _vals; }; Is the extra dereference essentially the same as the vtable lookup? What is the established idiom for this type of situation? Are both of these solutions dumb? Any insights are greatly appreciated

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• vectorize is indeterminate

  - by telliott99

  I'm trying to vectorize a simple function in numpy and getting inconsistent behavior. I expect my code to return 0 for values < 0.5 and the unchanged value otherwise. Strangely, different runs of the script from the command line yield varying results: sometimes it works correctly, and sometimes I get all 0's. It doesn't matter which of the three lines I use for the case when d <= T. It does seem to be correlated with whether the first value to be returned is 0. Any ideas? Thanks. import numpy as np def my_func(d, T=0.5): if d > T: return d #if d <= T: return 0 else: return 0 #return 0 N = 4 A = np.random.uniform(size=N**2) A.shape = (N,N) print A f = np.vectorize(my_func) print f(A) $ python x.py [[ 0.86913815 0.96833127 0.54539153 0.46184594] [ 0.46550903 0.24645558 0.26988519 0.0959257 ] [ 0.73356391 0.69363161 0.57222389 0.98214089] [ 0.15789303 0.06803493 0.01601389 0.04735725]] [[ 0.86913815 0.96833127 0.54539153 0. ] [ 0. 0. 0. 0. ] [ 0.73356391 0.69363161 0.57222389 0.98214089] [ 0. 0. 0. 0. ]] $ python x.py [[ 0.37127366 0.77935622 0.74392301 0.92626644] [ 0.61639086 0.32584431 0.12345342 0.17392298] [ 0.03679475 0.00536863 0.60936931 0.12761859] [ 0.49091897 0.21261635 0.37063752 0.23578082]] [[0 0 0 0] [0 0 0 0] [0 0 0 0] [0 0 0 0]]

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• Haskell: Dealing With Types And Exceptions

  - by Douglas Brunner

  I'd like to know the "Haskell way" to catch and handle exceptions. As shown below, I understand the basic syntax, but I'm not sure how to deal with the type system in this situation. The below code attempts to return the value of the requested environment variable. Obviously if that variable isn't there I want to catch the exception and return Nothing. getEnvVar x = do { var <- getEnv x; Just var; } `catch` \ex -> do { Nothing } Here is the error: Couldn't match expected type `IO a' against inferred type `Maybe String' In the expression: Just var In the first argument of `catch', namely `do { var <- getEnv x; Just var }' In the expression: do { var <- getEnv x; Just var } `catch` \ ex -> do { Nothing } I could return string values: getRequestURI x = do { requestURI <- getEnv x; return requestURI; } `catch` \ex -> do { return "" } however, this doesn't feel like the Haskell way. What is the Haskell way?

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• Pointer inside a struct / thread

  - by bruno

  Hi! I have this warning "warning: assignment from incompatible pointer type " in this line: data1->transformed_block[l] = &transformed_block[l]; - void print_message_function ( void *ptr ) { dt *data; data = (dt *) ptr; printf("Dentro da thread Numero0: %ld\n", data->L_norm_NewBlock); pthread_exit(0); } typedef struct data_thread { long L_norm_NewBlock; int Bsize_X; int Bsize_Y; int *transformed_block[MAX_LEVEL]; long L_norm_OrigBlock; } dt; void function() { int *transformed_block[MAX_LEVEL]; pthread_t thread1; dt *data1; pthread_attr_t attr; pthread_attr_init(&attr); //Fills structure data1 = (dt *) malloc(sizeof(dt)); data1->transformed_block[l] = &transformed_block[l]; data1->L_norm_NewBlock=0; data1->Bsize_Y = Bsize_Y; data1->Bsize_X = Bsize_X; pthread_create(&thread1, &attr, (void *) &print_message_function, (void *) &data1); } I want to get rid of that warning, and the values i get inside the thread are wrong. For example data1-L_norm_NewBlock=0; in the thread guives me a differente value (not 0 like it should be).

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• Rails: creating a model in the new action

  - by Joseph Silvashy

  I have an interesting situation, well it's probably not that unique at all, but I'm not totally sure how to tackle it. I have a model, in this case a recipe and the user navigates to the new path /recipes/new however the situation is that I need to be able to have the user upload images and make associations to that model in the new action, but the model doesn't have an ID yet. So I assume I need to rethink my controller, but I don't want to have redirects and whatnot, how can accomplish this? Here is the basic controller, barebones obviously: ... def new # I should be creating the model first, so it has an ID @recipe = Recipe.new end def create @recipe = Recipe.new(params[:recipe]) if @recipe.save redirect_to @recipe else render 'new' end end ... update Perhaps I can have a column thats like state which could have values like new/incomplete/complete or what-have-you. I'm mostly trying to figure out what would also be most efficient for the DB. It would be nice if I could still have a url that said '/new', instead of it be the edit path with the id, for usability sake, but I'm not sure this can be simply accomplished in the new action of my controller. Thoughts?

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• Prototype: Form.serialize missing some inputs (due to table?)

  - by Chris

  I'm using JavaScript Prototype (through Ruby on Rails) to handle some Ajax calls; but in one particular case I'm missing a field from the form. I have a layout like this: +---------+---------+ | Thing 1 | Thing 2 | +---------+---------+-----------+ | o Opt 1 | o Opt 1 | <Confirm> | | o Opt 2 | o Opt 2 | | +---------+---------+-----------+ Opt 1 and 2 are Radio buttons, Confirm is a button. The entire table is wrapped in a form, with code like: <form action="javascript:void(0)"> <input type="hidden" name="context" value="foo" /> <input type="hidden" name="subcontext" value="bar" /> <table> <tr><td>Thing 1</td><td>Thing2</td></tr> <tr><td> <input type="radio" name="choice" value="1.1" />Opt 1<br /> <input type="radio" name="choice" value="1.2" />Opt 2<br /> </td><td> <input type="radio" name="choice" value="2.1" />Opt 1<br /> <input type="radio" name="choice" value="2.2" />Opt 2<br /> </td><td> <input name="choice_btn" type="button" value="Confirm" onclick="new AJAX.Updater('my_form', '/process_form', {asynchronous:true, evalScripts:true, parameters:Form.serialize(this.form)}); return false;" /> </td></tr> </table> </form> But I can see that the POST generated by clicking the Confirm button contains the foo and bar values for the hidden fields, but not the choice of the radio buttons. Is this because I've got a table inside my form? How can I get around this?

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• PHP: Three item validation comparison

  - by DavidYell

  I have 3 featured product panels on the homepage, and I'm writing a CMS page for it. I'm trying to validate the items. They are selected via three <select> elements, featured1, featured2 and featured3. The default is <option value="0" selected>Select an element</option> I need to validate the $_POST to ensure that the user hasn't selected the same product for more than one of the panels. I have worked out that each $_POST needs to be $_POST['featuredN'] > 0 but I can't seem to find a logical way of processing the 7 potential outcomes. Using a logic table, where 1 is a set value. 1 2 3 ------- 0 0 0 1 1 1 1 0 0 0 1 0 0 0 1 1 1 0 0 1 1 If an item is 0, then I will not update it, but I want the user to be able to update a single item if needs be. I cannot find a logical way to see if the item is not 0, and then compare it to another item if that also is not 0. So far my colleague suggested, adding up the values. Which works to see if condition 1 0 0 0 is not met. I have a vague feeling that some form of recursive function might be in order, but I can't quite get my brain to help me on this one! So to the collective brain! :)

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• visual analysis of web pages in ruby

  - by Clint Miller

  I'm looking to write some code that does visual analysis of web pages, preferably using Ruby. My code will need to be able to determine the top, left, width, height, background color, color, and font size for all the elements in the DOM. Of course, these values can only be calculated once all CSS is applied. So, I don't think that Nokogiri is up for the job. Ultimately, I'm trying to use this data in a VIPS-like (Vision-Based Page Segmentation) algorithm in an attempt to find the main content in downloaded news articles. I've considered using Watir to drive Chrome or Firefox and then extract the data. The problem is that browsers can't be run headless through Watir (I think). Ultimately, this code will be running on an array of Linux servers in a data center. So, the code won't have easy access to an X Server for displaying the browser. I suppose one solution is to use Watir and run a headless X Server on the Linux servers. That's a bit of a pain, but it looks like my best option right now. Does anyone have any better ideas?

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• connecting to mysql from excel: ODBC driver does not support the requested properties.

  - by every_answer_gets_a_point

  i am trying to add data to mysql from excel. i am getting the above error on this line: rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic here is my code: Dim oConn As ADODB.Connection Private Sub ConnectDB() Set oConn = New ADODB.Connection oConn.Open "DRIVER={MySQL ODBC 5.1 Driver};" & _ "SERVER=localhost;" & _ "DATABASE=employees;" & _ "USER=root;" & _ "PASSWORD=some_pass;" & _ "Option=3" End Sub Function esc(txt As String) esc = Trim(Replace(txt, "'", "\'")) End Function Private Sub InsertData() Dim rs As ADODB.Recordset Set rs = New ADODB.Recordset ConnectDB With wsBooks For rowCursor = 2 To 11 strSQL = "INSERT INTO tutorial (author, title, price) " & _ "VALUES ('" & esc(.Cells(rowCursor, 1)) & "', " & _ "'" & esc(.Cells(rowCursor, 2)) & "', " & _ esc(.Cells(rowCursor, 3)) & ")" rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic Next End With End Sub whats wrong with rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic ? why am i getting the odbc error?

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• Strange behaviour of DataTable with DataGridView

  - by Paul

  Please explain me what is happening. I have created a WinForms .NET application which has DataGridView on a form and should update database when DataGridView inline editing is used. Form has SqlDataAdapter _da with four SqlCommands bound to it. DataGridView is bound directly to DataTable _names. Such a CellValueChanged handler: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { _da.Update(_names); } does not update database state although _names DataTable is updated. All the rows of _names have RowState == DataRowState.Unchanged Ok, I modified the handler: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { DataRow row = _names.Rows[e.RowIndex]; row.BeginEdit(); row.EndEdit(); _da.Update(_names); } this variant really writes modified cell to database, but when I attempt to insert new row into grid, I get an error about an absence of row with index e.RowIndex So, I decided to improve the handler further: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { if (_names.Rows.Count<e.RowIndex) { DataRow row = _names.Rows[e.RowIndex]; row.BeginEdit(); row.EndEdit(); } else { DataRow row = _names.NewRow(); row["NameText"] = dataGridView1["NameText", e.RowIndex].Value; _names.Rows.Add(row); } _da.Update(_names); } Now the really strange things happen when I insert new row to grid: the grid remains what it was until _names.Rows.Add(row); After this line THREE rows are inserted into table - two rows with the same value and one with Null value. The slightly modified code: DataRow row = _names.NewRow(); row["NameText"] = "--------------" _names.Rows.Add(row); inserts three rows with three different values: one as entered into the grid, the second with "--------------" value and third - with Null value. I really got stuck in guessing what is happening.

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• Databinding to the DataGridView (Enums + Collections)

  - by Ian

  I'm after a little help with the techniques to use for Databinding. It's been quite a while since I used any proper data binding and want to try and do something with the DataGridView. I'm trying to configure as much as possible so that I can simply designed the DatagridView through the form editor, and then use a custom class that exposes all my information. The sort of information I've got is as follows: public class Result { public String Name { get; set; } public Boolean PK { get; set; } public MyEnum EnumValue { get; set; } public IList<ResultInfos> { get; set; } } public class ResultInfos { get; set; } { public class Name { get; set; } public Int Value { get; set; } public override String ToString() { return Name + " : " Value.ToString(); } } I can bind to the simple information without any problem. I want to bind to the EnumValue with a DataGridViewComboBoxColumn, but when I set the DataPropertyName I get exceptions saying the enum values aren't valid. Then comes the ResultInfo collection. Currently I can't figure out how to bind to this and display my items, again really I want this to be a combobox, where the 1st Item is selected. Anyone any suggestions on what I'm doing wrong? Thanks

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• Implementation help... Subclass NSManagedObject?

  - by Canada Dev

  I'm working on an app where I have some products that I download in a list. The downloaded products are displayed in a table and each will is showing a detail view with more information. These same products can be saved as a favorite, and for this I am using Core Data. I'd like to be able to re-use a bunch of views for displaying the products, which means the stores object and the downloaded object would have to be the same kind. Now, how would I go about best implementing the objects? Can I make a class such as this: FavoriteProduct : NSManageObject // implementation and then subclass Product : FavoriteProduct // implementation ? The CD class just doesn't give me everything. What would be the best way to merge these two object classes so I have as little work ahead of me in terms of implementing the different views for each object? Basically, I just want to be able to call the same methods, etc. on the Product objects as I would on the ones that are FavoriteProduct objects, and re-use views for both kinds. There's only a bit of difference between the two (one is of course stored as a favorite and has some extra values such as notes, tags, while the Product one doesn't). Thanks in advance

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• LINQ: display results from empty lists

  - by Douglas H. M.

  I've created two entities (simplified) in C#: class Log { entries = new List<Entry>(); DateTime Date { get; set; } IList<Entry> entries { get; set; } } class Entry { DateTime ClockIn { get; set; } DateTime ClockOut { get; set; } } I am using the following code to initialize the objects: Log log1 = new Log() { Date = new DateTime(2010, 1, 1), }; log1.Entries.Add(new Entry() { ClockIn = new DateTime(0001, 1, 1, 9, 0, 0), ClockOut = new DateTime(0001, 1, 1, 12, 0, 0) }); Log log2 = new Log() { Date = new DateTime(2010, 2, 1), }; The method below is used to get the date logs: var query = from l in DB.GetLogs() from e in l.Entries orderby l.Date ascending select new { Date = l.Date, ClockIn = e.ClockIn, ClockOut = e.ClockOut, }; The result of the above LINQ query is: /* Date | Clock In | Clock Out 01/01/2010 | 09:00 | 12:00 */ My question is, what is the best way to rewrite the LINQ query above to include the results from the second object I created (Log2), since it has an empty list. In the other words, I would like to display all dates even if they don't have time values. The expected result would be: /* Date | Clock In | Clock Out 01/01/2010 | 09:00 | 12:00 02/01/2010 | | */

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• python matrices - list index out of range

  - by user1888493

  I am writing a function, that takes a matrix as input, such as the one below. Then the it returns the matrix' inverse, where all the 1s are changed to 0s and all the 0s changed to 1s, while keeping the diagonal from top left to bottom right 0s. An example input: g1 = [[0, 1, 1, 0], [1, 0, 0, 1], [1, 0, 0, 1], [0, 1, 1, 0]] the function should output this: g1 = [[0, 0, 0, 1], [0, 0, 1, 0], [0, 1, 0, 0], [1, 0, 0, 0]] When I run the program, it raises a list index out of range error. I'm sure this happens, because the loops I have set up are trying to access values that do not exist. But how do I allow an input of unknown row and column size? I only know how to do this with a single list, but a list of lists? Following you see the transforming function, but not the test function that calls it: def inverse_graph(graph): # take in graph # change all zeros to ones and ones to zeros r, c = 0, 0 # row, column equal zero while (graph[r][c] == 0 or graph[r][c] == 1): # while the current row has a value. while (graph[r][c] == 0 or graph[r][c] == 1): # while the current column has a value if (graph[r][c] == 0): graph[r][c] = 1 elif (graph[r][c] == 1): graph[r][c] = 0 c+=1 c=0 r+=1 c=0 r=0 # sets diagonal to zeros while (g1[r][c] == 0 or g1[r][c] == 1): g1[r][c]=0 c+=1 r+=1 return graph

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• Relating text fields to check boxes in Java

  - by Finzz

  This program requires the user to login and request a database to access. The program then gets a connection object, searches through the database storing the column names into a vector for later use. The problem comes with implementing text fields to allow the user to search for specific values within the database. I can get the check boxes and text fields to appear using a gridlayout and add them to a panel. How do I relate the text fields to their appropriate check box? I've tried adding them to a vector, but then they can't also be added to the panel as well. I've searched for a way to name the text fields as the loop cycles through the column names, but it seems impossible to do without having them declared ahead of time. This can't be done either, as it's impossible to determine the attributes that the user will request. I just need to be able to know the names of the text fields so I can test to see if the user entered information and perform the necessary logic. Let me know if you have to see the rest of the code to give an answer, but hopefully you get the general idea of what I'm trying to accomplish. Picture of UI: try { ResultSet r2 = con.getMetaData().getColumns("", "", rb.getText(), ""); colNames1 = new Vector<String>(); columns1 = new Vector<JCheckBox>(); while (r2.next()) { colNames1.add(r2.getString(4)); JCheckBox cb = new JCheckBox(r2.getString(4)); JTextField tf = new JTextField(10); columns1.add(cb); p3.add(cb); p3.add(tf); } }

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