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DataGridColumnCollection Class

A collection of DataGridColumn-derived column objects that represent the columns in a DataGrid control. This class cannot be inherited.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

public sealed class DataGridColumnCollection : ICollection, IEnumerable, IStateManager
public final class DataGridColumnCollection implements ICollection, IEnumerable, 
	IStateManager
public final class DataGridColumnCollection implements ICollection, IEnumerable, 
	IStateManager

Use the DataGridColumnCollection collection to programmatically manage a collection of DataGridColumn-derived column objects. These objects represent the columns in a DataGrid control. You can add, remove, or insert columns in the DataGridColumnCollection collection.

NoteNote

When the AutoGenerateColumns property is set to true, the columns created by the DataGrid control are not added to the Columns collection.

The DataGrid control does not store the contents of its Columns collection in the view state. To add or remove a column dynamically, you must programmatically add or remove the column every time the page is refreshed. Provide a Page_Init function that adds or removes the column before the DataGrid control's state is reloaded and the control is rebuilt. Otherwise, the changes to the Columns collection are not reflected in the DataGrid control when it is displayed.

NoteNote

Although you can programmatically add columns to or remove columns from the Columns collection of the DataGrid control, it is easier to list the columns statically and then use the Visible property to display or hide each column.

The order of the columns in the collection determines the order that the columns are displayed in the DataGrid control.

The following table lists the different column classes that derive from the DataGridColumn class.

Column Class

Description

BoundColumn

A column that is bound to a field in a data source. It displays each item in the field as text. This is the default column type for the DataGrid control.

ButtonColumn

A column that displays a command button for each item in the column. This allows you to create a column of custom button controls, such as Add or Remove buttons.

EditCommandColumn

A column that contains editing commands for each item in the column.

HyperLinkColumn

A column that displays each item in the column as a hyperlink. The contents of the column can be bound to a field in a data source, or to static text.

TemplateColumn

A column that displays each item in the column according to a specified template. This allows you to control the content of the column, for example to display images.

NoteNote

The DataGridColumn class is the base class for the column classes listed. It is not used directly in the DataGridColumnCollection collection.

The following code example demonstrates how to use the DataGridColumnCollection collection to dynamically add a column to the DataGrid control. Note that the Columns property of the DataGrid control is an instance of the DataGridColumnCollection class.


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
   <script runat="server">

      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;

      }
 
      void Page_Load(Object sender, EventArgs e) 
      {

         // Create a DataGrid control.
         DataGrid ItemsGrid = new DataGrid();

         // Set the properties of the DataGrid.
         ItemsGrid.ID = "ItemsGrid";
         ItemsGrid.BorderColor = System.Drawing.Color.Black;
         ItemsGrid.CellPadding = 3;
         ItemsGrid.AutoGenerateColumns = false;

         // Set the styles for the DataGrid.
         ItemsGrid.HeaderStyle.BackColor = 
             System.Drawing.Color.FromArgb(0x0000aaaa);

         // Create the columns for the DataGrid control. The DataGrid
         // columns are dynamically generated. Therefore, the columns   
         // must be re-created each time the page is refreshed.
         
         // Create and add the columns to the collection.
         ItemsGrid.Columns.Add(CreateBoundColumn("IntegerValue", "Item"));
         ItemsGrid.Columns.Add(
             CreateBoundColumn("StringValue", "Description"));
         ItemsGrid.Columns.Add(
             CreateBoundColumn("CurrencyValue", "Price", "{0:c}", 
             HorizontalAlign.Right));
         ItemsGrid.Columns.Add(
             CreateLinkColumn("http://www.microsoft.com", "_self", 
             "Microsoft", "Related link"));
        
         // Specify the data source and bind it to the control.
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();

         // Add the DataGrid control to the Controls collection of 
         // the PlaceHolder control.
         Place.Controls.Add(ItemsGrid);

      }

      BoundColumn CreateBoundColumn(String DataFieldValue, 
          String HeaderTextValue)
      {

         // This version of the CreateBoundColumn method sets only the
         // DataField and HeaderText properties.

         // Create a BoundColumn.
         BoundColumn column = new BoundColumn();

         // Set the properties of the BoundColumn.
         column.DataField = DataFieldValue;
         column.HeaderText = HeaderTextValue;

         return column;

      }

      BoundColumn CreateBoundColumn(String DataFieldValue, 
          String HeaderTextValue, String FormatValue, 
          HorizontalAlign AlignValue)
      {

         // This version of CreateBoundColumn method sets the DataField,
         // HeaderText, and DataFormatString properties. It also sets the 
         // HorizontalAlign property of the ItemStyle property of the column. 

         // Create a BoundColumn using the overloaded CreateBoundColumn method.
         BoundColumn column = CreateBoundColumn(DataFieldValue, HeaderTextValue);

         // Set the properties of the BoundColumn.
         column.DataFormatString = FormatValue;
         column.ItemStyle.HorizontalAlign = AlignValue;

         return column;

      }

      HyperLinkColumn CreateLinkColumn(String NavUrlValue, 
          String TargetValue, String TextValue, String HeaderTextValue)
      {

         // Create a BoundColumn.
         HyperLinkColumn column = new HyperLinkColumn();

         // Set the properties of the ButtonColumn.
         column.NavigateUrl = NavUrlValue;
         column.Target = TargetValue;
         column.Text = TextValue;
         column.HeaderText = HeaderTextValue;

         return column;

      }

   </script>
 
<body>
 
   <form runat=server>
 
      <h3>DataGrid Constructor Example</h3>
 
      <b>Product List</b>

      <asp:PlaceHolder id="Place"
           runat="server"/>
 
   </form>
 
</body>
</html>


System.Object
  System.Web.UI.WebControls.DataGridColumnCollection
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0
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