Search Results

Search found 2511 results on 101 pages for 'datagridview trick'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 14/101 | < Previous Page | 10 11 12 13 14 15 16 17 18 19 20 21  | Next Page >

  • Template trick to optimize out allocations

    - by anon
    I have: struct DoubleVec { std::vector<double> data; }; DoubleVec operator+(const DoubleVec& lhs, const DoubleVec& rhs) { DoubleVec ans(lhs.size()); for(int i = 0; i < lhs.size(); ++i) { ans[i] = lhs[i]] + rhs[i]; // assume lhs.size() == rhs.size() } return ans; } DoubleVec someFunc(DoubleVec a, DoubleVec b, DoubleVec c, DoubleVec d) { DoubleVec ans = a + b + c + d; } Now, in the above, the "a + b + c + d" will cause the creation of 3 temporary DoubleVec's -- is there a way to optimize this away with some type of template magic ... i.e. to optimize it down to something equivalent to: DoubleVec ans(a.size()); for(int i = 0; i < ans.size(); i++) ans[i] = a[i] + b[i] + c[i] + d[i]; You can assume all DoubleVec's have the same # of elements. The high level idea is to have do some type of templateied magic on "+", which "delays the computation" until the =, at which point it looks into itself, goes hmm ... I'm just adding thes numbers, and syntheizes a[i] + b[i] + c[i] + d[i] ... instead of all the temporaries. Thanks!

    Read the article

  • Trick to getting initWithNibFile to be invoked?

    - by PhazeZero
    I've implemented a View Controller, and I'm trying to do some very basic initialization in initWithNibFile...which I understand to be the designated initializer for View Controller objects. I've tried to put breakpoints on the code, and have put very simple NSLog statements into it as well. Regardless...I'm not seeing it be executed (and the object i'm attempting to alloc/init inside the function is also not being allocated - so I'm about 99% sure I'm not hitting the code. Is there something I need to do elsewhere to cause this method to be invoked? I'm getting a clean build, no warnings or errors. And the app successfully loads up the View, and I can invoke a ButtonClick method I've coded and connected to this same View Controller. Any suggestions would be appreciated. TC

    Read the article

  • how to send data to server with the same TCP connection using ajax or JS trick

    - by zack
    Hi, I know how to keep a connection indifinetely open server side to stream continuously data to javascript. BUT I do not know how to send data reusing the same TCP from browser to server. so there is not the 3 way handshake and only 2 tcp packets. I know it is possible but I do not how to do it : use xmlhttprequest? or script tag ajax ? can you tell me how to do it. thank you very much

    Read the article

  • Undefined template methods trick ?

    - by Matthieu M.
    A colleague of mine told me about a little piece of design he has used with his team that sent my mind boiling. It's a kind of traits class that they can specialize in an extremely decoupled way. I've had a hard time understanding how it could possibly work, and I am still unsure of the idea I have, so I thought I would ask for help here. We are talking g++ here, specifically the versions 3.4.2 and 4.3.2 (it seems to work with both). The idea is quite simple: 1- Define the interface // interface.h template <class T> struct Interface { void foo(); // the method is not implemented, it could not work if it was }; // // I do not think it is necessary // but they prefer free-standing methods with templates // because of the automatic argument deduction // template <class T> void foo(Interface<T>& interface) { interface.foo(); } 2- Define a class, and in the source file specialize the interface for this class (defining its methods) // special.h class Special {}; // special.cpp #include "interface.h" #include "special.h" // // Note that this specialization is not visible outside of this translation unit // template <> struct Interface<Special> { void foo() { std::cout << "Special" << std::endl; } }; 3- To use, it's simple too: // main.cpp #include "interface.h" class Special; // yes, it only costs a forward declaration // which helps much in term of dependencies int main(int argc, char* argv[]) { Interface<Special> special; foo(special); return 0; }; It's an undefined symbol if no translation unit defined a specialization of Interface for Special. Now, I would have thought this would require the export keyword, which to my knowledge has never been implemented in g++ (and only implemented once in a C++ compiler, with its authors advising anyone not to, given the time and effort it took them). I suspect it's got something to do with the linker resolving the templates methods... Do you have ever met anything like this before ? Does it conform to the standard or do you think it's a fortunate coincidence it works ? I must admit I am quite puzzled by the construct...

    Read the article

  • PHP's form bracket trick is to Django's ___?

    - by Matt
    In PHP you can create form elements with names like: category[1] category[2] or even category[junk] category[test] When the form is posted, category is automatically turned into a nice dictionary like: category[1] => "the input value", category[2] => "the other input value" Is there a way to do that in Django? request.POST.getlist isn't quite right, because it simply returns a list, not a dictionary. I need the keys too.

    Read the article

  • Bizarre static_cast trick?

    - by Rob
    While perusing the Qt source code I came across this gem: template <class T> inline T qgraphicsitem_cast(const QGraphicsItem *item) { return int(static_cast<T>(0)->Type) == int(QGraphicsItem::Type) || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0; } Notice the static_cast<T>(0)->Type? I've been using C++ for many years but have never seen 0 being used in a static_cast before. What is this code doing and is it safe? Background: If you derive from QGraphicsItem you are meant to declare an unique enum value called Type that and implement a virtual function called type that returns it, e.g.: class Item : public QGraphicsItem { public: enum { Type = MAGIC_NUMBER }; int type() const { return Type; } ... }; You can then do this: QGraphicsItem* item = new Item; ... Item* derivedItem = qgraphicsitem_cast<Item*>(item); This will probably help explain what that static_cast is trying to do.

    Read the article

  • C# Same DataSource + Multiple DataGridViews = Data Binding Issues?

    - by C. Griffin
    Here's what I'm doing: I have (2) DataGridView controls DGV #1 is bound to the DataSet, DGV #2 is bound to a DataView of the SAME DataSet Now, what I'm needing to accomplish here is this: When a user checks a boolean column on the original DGV, the second DGV should now display the newly checked row also. The context is that the first DGV is a master list, and the second one is a "favorite" view of the first. When I check the rows, the favorite column does NOT update. Do I need to use a DataAdapter to actually update the database, or can I operate directly on the DataSet (DataTable) -- or even with the Rows in the original DataGridView?

    Read the article

  • Usercontrol databinding within a databound datagridview

    - by user328259
    Good day. I'm developing a Windows application and working with Windows Forms; .Net 2.0. I have an issue databinding a generic List of Car Rental Companies to a DataGridView when that list contains (one of its properties) anoother generic List of Car Makes. I also have a UserControl that I need to bind to this [inner] generic list ... Class CarRentalCompany contains: string Name, string Location, List CarMakes Class CarMake contains: string Name, bool isFord, bool isChevy, bool isOther The UserControl has a label for CarMake.Name and 3 checkboxes for each of the booleans of the class. HOw do I make this user control bindable for the class? In my form, I have a DataGridView binded to the CarRentalCompany object. The list CarMakes could be 0 or more items and I can add these as necessary. How do I establish the binding of CarRentalCompanies properly so CarMakes will bind accordingly?? For example, I have: List CarRentalCompanies = new List(); CarRentalCompany company1 = new CarRentalCompany(); company1.Name = "Acme Rentals"; company1.Location = "New York, NY"; company1.CarMakes = new List<CarMake>(); CarMake car1 = new CarMake(); car1.Name = "The Yellow Car"; car1.isFord = true; car1.isChevy = false; car1.isOther = false; company1.CarMakes.Add(car1); CarMake car2 = new CarMake(); car2.Name = "The Blue Car"; car2.isFord = false; car2.isChevy = true; car2.isOther = false; company1.CarMakes.Add(car2); CarMake car3 = new CarMake(); car3.Name = "The Purple Car"; car3.isFord = false; car3.isChevy = false; car3.isOther = true; company1.CarMakes.Add(car3); CarRentalCompanies.Add(company1); CarRentalCompany company2 = new CarRentalCompany(); company1.Name = "Z-Auto Rentals"; company1.Location = "Phoenix, AZ"; company1.CarMakes = new List<CarMake>(); CarMake car4 = new CarMake(); car4.Name = "The OrangeCar"; car4.isFord = true; car4.isChevy = false; car4.isOther = false; company2.CarMakes.Add(car4); CarMake car5 = new CarMake(); car5.Name = "The Red Car"; car5.isFord = true; car5.isChevy = false; car5.isOther = false; company2.CarMakes.Add(car5); CarMake car6 = new CarMake(); car6.Name = "The Green Car"; car6.isFord = true; car6.isChevy = false; car6.isOther = false; company2.CarMakes.Add(car6); CarRentalCompanies.Add(company2); I load my form and in my load form I have the following: Note: CarDataGrid is a DataGridView BindingSource bsTheRentals = new BindingSource(); DataGridViewTextBoxColumn companyName = new DataGridViewTextBoxColumn(); companyName.DataPropertyName = "Name"; companyName.HeaderText = "Company Name"; companyName.Name = "CompanyName"; companyName.AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells; DataGridViewTextBoxColumn companyLocation = new DataGridViewTextBoxColumn(); companyLocation.DataPropertyName = "Location"; companyLocation.HeaderText = "Company Location"; companyLocation.Name = "CompanyLocation"; companyLocation.AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells; ArrayList carMakeColumnsToAdd = new ArrayList(); // Loop through the CarMakes list to add each custom column for (int intX=0; intX < CarRentalCompanies.CarMakes[0].Count; intX++) { // Custom column for user control string carMakeColumnName = "carColumn" + intX; CarMakeListColumn carMakeColumn = new DataGridViewComboBoxColumn(); carMakeColumn.Name = carMakeColumnName; carMakeColumn.DisplayMember = CarRentalCompanies.CarMakes[intX].Name; carMakeColumn.DataSource = CarRentalCompanies.CarMakes; // this is the CarMAkes List carMakeColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill; carMakeColumnsToAdd.Add(carMakeColumn); } CarDataGrid.DataSource = bsTheRentals; CarDataGrid.Columns.AddRange(new DataGridViewColumn[] { companyName, companylocation, carMakeColumnsToAdd }); CarDataGrid.AutoGenerateColumns = false; The code I provided does not work because I am unfamiliar with UserControls and custom DataGridViewColumns and DataGridViewCells - I know I must derive from these classes in order to use my User Control properly. I appreciate any advice/assistance/help in this. Thank you. Lawrence

    Read the article

  • how to get out information from datagridview ???

    - by ghost_j1
    hi everyone I am working on program that calculate the GBA for university student in visual c# So i make an datagridview that contain columns for each subject and its mark as later and number but after the user "student" insert his subject i want to let him to press button that get the mark and the number of the cirdit hours of each subject and calculate the GBA for the student and put the result in textbox... does anyone can help me to do it ???

    Read the article

  • Add Imagebutton to DataGridView in C#

    - by espais
    I am trying to do a simple 'Delete Row' button in a DataGridView that I have, but the problem is that I would like it to be an ImageButton rather than a simple Button. Currently I have it setup to be a ButtonColumn, but have seen no possibility for changing it from a simple button with text to a button with an image on it. I know this is possible and hopefully relatively simple, but am unsure of how to go about doing it.

    Read the article

  • how to work with datagridview if need show many columns data (approx 1Mio)

    - by ruprog
    is a problem to display data in Datagridview. A large amount of data (stock quotes) data to be displayed from left to right Tell me what to do to display an array of data in datagridviev Public dat As New List(Of act) Public Class act Public time As Date Public price As Integer End Class Sub work() Dim r As New Random For x As Integer = 0 To 1000000 Dim el As New act el.time = Now el.price = r.Next(0, 1000) dat.Add(New act) Next End Sub

    Read the article

  • Programmatically adding an object and selecting the correspondig row does not make it become the CurrentRow

    - by Robert
    I'm in a struggle with the DataGridView: I do have a BindingList of some simple objects that implement INotifyPropertyChanged. The DataGridView's datasource is set to this BindingList. Now I need to add an object to the list by hitting the "+" key. When an object is added, it should appear as a new row and it shall become the current row. As the CurrentRow-property is readonly, I iterate through all rows, check if its bound item is the newly created object, and if it is, I set this row to "Selected = true;" The problem: although the new object and thereby a new row gets inserted and selected in the DataGridView, it still is not the CurrentRow! It does not become the CurrentRow unless I do a mouse click into this new row. In this test program you can add new objects (and thereby rows) with the "+" key, and with the "i" key the data-bound object of the CurrentRow is shown in a MessageBox. How can I make a newly added object become the CurrentObject? Thanks for your help! Here's the sample: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { BindingList<item> myItems; public Form1() { InitializeComponent(); myItems = new BindingList<item>(); for (int i = 1; i <= 10; i++) { myItems.Add(new item(i)); } dataGridView1.DataSource = myItems; } public void Form1_KeyDown(object sender, KeyEventArgs e) { if (e.KeyCode == Keys.Add) { addItem(); } } public void addItem() { item i = new item(myItems.Count + 1); myItems.Add(i); foreach (DataGridViewRow dr in dataGridView1.Rows) { if (dr.DataBoundItem == i) { dr.Selected = true; } } } private void btAdd_Click(object sender, EventArgs e) { addItem(); } private void dataGridView1_KeyDown(object sender, KeyEventArgs e) { if (e.KeyCode == Keys.Add) { addItem(); } if (e.KeyCode == Keys.I) { MessageBox.Show(((item)dataGridView1.CurrentRow.DataBoundItem).title); } } } public class item : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; private int _id; public int id { get { return _id; } set { this.title = "This is item number " + value.ToString(); _id = value; InvokePropertyChanged(new PropertyChangedEventArgs("id")); } } private string _title; public string title { get { return _title; } set { _title = value; InvokePropertyChanged(new PropertyChangedEventArgs("title")); } } public item(int id) { this.id = id; } #region Implementation of INotifyPropertyChanged public void InvokePropertyChanged(PropertyChangedEventArgs e) { PropertyChangedEventHandler handler = PropertyChanged; if (handler != null) handler(this, e); } #endregion } }

    Read the article

  • DataGridViewColumn.DataPropertyName Property

    - by Captain Comic
    Hi I have a DataGridView control and I want to populate it with data. I use DataSource property // dgvDealAsset is DataGridView private void DealAssetListControl_Load(object sender, EventArgs e) { dgvDealAssets.AutoGenerateColumns = false; dgvDealAssets.DataSource = DealAssetList.Instance.Values.ToList(); } Now problem number one. The class of my collection does not contain only simple types that I can map to columns using DataPropertyName. This is the class that is contained in collection. class MyClass { public String Name; MyOtherClass otherclass; } class MyOtherClass { public String Name; } Now I am binding properties of MyClass to columns col1.DataPropertyName = "Name" // Ok col2.DataPropertyName = "otherclass" // Not OK - I will have empty cell The problem is that I want to display otherclass.Name field. But if I try to write col2.DataPropertyName = "otherclass.Name" I get empty cell. I tried to manually set the column private void DealAssetListControl_Load(object sender, EventArgs e) { dgvDealAssets.AutoGenerateColumns = false; dgvDealAssets.DataSource = DealAssetList.Instance.Values.ToList(); // iterate through rows and set the column manually foreach (DataGridViewRow row in dgvDealAssets.Rows) { row.Cells["Column2"].Value = ((DealAsset)row.DataBoundItem).otherclass.Name; } But this foreach cycle takes about minute to complete (2k elements). How to solve this problem?

    Read the article

  • how can I add a custom non-DataTable column to my DataView, in a winforms ADO.net application?

    - by Greg
    Hi, How could I (/is it possible) to add a custom column to my DataView, and in this column display the result of a specific calculation. That is, I currently have a dataGridView which has a binding to a DataView, based on the DataTable from my database. I'd like to add an additional column to the dataGridView to display a number which is calculated by looking at this current row plus it's children row. In other words the info for the column isn't just derivable from the row data itself. Specific questions might be: a) where to add the column itself? to the DataView I assume? b) which method / event to trigger the re-calculation of the value of this custom column from ( / how do I control this) Thanks PS. I've also noted if I use the following code/approach I get a infinite loop... // Custom Items DataColumn dc = new DataColumn("OverallSize", typeof(long)); DT_Webfiles.Columns.Add(dc); DT_Webfiles.RowChanged += new DataRowChangeEventHandler(DT_Row_Changed); private static void DT_Row_Changed(object sender, DataRowChangeEventArgs e) { e.Row["OverallSize"] = e.Row["OverallSize"] ?? 0; e.Row["OverallSize"] = (long)e.Row["OverallSize"] + 1; } What other approach could avoid this looping. i.e. currently I'm saying update the value of the custom column when the row changes, however after then changing the row it triggers antoher 'row has changed' event...

    Read the article

  • DatagGridViewColumn.DataPropertyName to an array element?

    - by unknown
    Hi there, I'm using a DataGridView binding its datasource to a List, and specifying the properties for each column. An example would be: DataGridViewTextBoxColumn colConcept = new DataGridViewTextBoxColumn(); DataGridViewCell cell4 = new DataGridViewTextBoxCell(); colConcept.CellTemplate = cell4; colConcept.Name = "concept"; colConcept.HeaderText = "Concept"; colConcept.DataPropertyName = "Concept"; colConcept.Width = 200; this.dataGridViewBills.Columns.Add(colConcept); {... assign other colums...} And finally this.dataGridViewBills.DataSource=billslist; //billslist is List<Bill> Obviously Class Bill has a Property called Concept, as well as one Property for each column. Well, now my problem, is that Bill should have and Array/List/whateverdynamicsizecontainer of strings called Years. Let's assume that every Bill will have the same Years.Count, but this only known at runtime.Thus, I can't specify properties like Bill.FirstYear to obtain Bill.Years[0], Bill.SecondYear to obtain Bills.Years[1]... etc... and bind it to each column. The idea, is that now I want to have a grid with dynamic number of colums (known at runtime), and each column filled with a string from the Bill.Years List. I can make a loop to add columns to the grid at runtime depending of Bill.Years.Count, but is possible to bind them to each of the strings that the Bill.Years List contains??? I'm not sure if I'm clear enough. The result ideally would be something like this, for 2 bills on the list, and 3 years for each bill: --------------------------------------GRID HEADER------------------------------- NAME CONCEPT YEAR1 YEAR2 YEAR3 --------------------------------------GRID VALUES------------------------------- Bill1 Bill1.Concept Bill1.Years[0] Bill1.Years[1] Bill1.Years[2] Bill2 Bill2.Concept Bill2.Years[0] Bill2.Years[1] Bill2.Years[2] I can always forget the datasource, and write each cell manually, as the MSFlexGrid used to like, but if possible, I would like to use the binding capabilities of the DataGridView. Any ideas? Thanks a lot.

    Read the article

  • multicolumn sorting of WinForms DataGridView

    - by Bi
    I have a DataGridView in a windows form with 3 columns: Serial number, Name, and Date-Time. The Name column will always have either of the two values: "name1" or "name2". I need to sort these columns such that the grid displays all the rows with name values in a specific order (first display all the "name1" rows and then all the "name2" rows). Within the "name1" rows, I want the rows to be sorted by the Date-Time. Please note programmatically, all the 3 columns are strings. For example, if I have the rows: 01 |Name1 | 2010-05-05 10:00 PM 02 |Name2 | 2010-05-02 08:00 AM 03 |Name2 | 2010-05-01 08:00 AM 04 |Name1 | 2010-05-01 11:00 AM 05 |Name1 | 2010-05-04 07:00 AM needs to be sorted as 04 |Name1 | 2010-05-01 11:00 AM 05 |Name1 | 2010-05-04 07:00 AM 01 |Name1 | 2010-05-05 10:00 PM 03 |Name2 | 2010-05-01 08:00 AM 02 |Name2 | 2010-05-02 08:00 AM I am not sure how to go about using the below: myGrid.Sort(.....,ListSortDirection.Ascending)

    Read the article

  • Problem using DataGridView Control of VB.NET 2008

    - by Tareq
    Hi, I am using VB.NET 2008 based on Framework 3.5 I use a datagridview control on a form and the form's load event as follows: Private Sub frmServiceSettings_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load With dgvFinishedProduct Dim myCombo As New DataGridViewComboBoxColumn ... I generate the combo here from the result of my database .Columns.Add(myCombo) End With End Sub Now when i want to get the data that is set in this column, there is no problem. But if I want to set the data programmatically, there arises problem. How can I solve the problem? If you want more info, please let me know.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 10 11 12 13 14 15 16 17 18 19 20 21  | Next Page >