DataGridColumnCollection.Clear Method ()
.NET Framework (current version)
Removes all DataGridColumn-derived column objects from the DataGridColumnCollection collection.
Assembly: System.Web (in System.Web.dll)
Use this method to remove all DataGridColumn-derived column objects from the DataGridColumnCollection collection.
Note |
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The Count property is automatically set to 0 after this method is used. |
The following code example demonstrates how to use the Clear method to empty the DataGridColumnCollection collection before adding new columns to the collection.
<%@ Page Language="C#" AutoEventWireup="True" %> <%@ Import Namespace="System.Data" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <script language="C#" runat="server"> ICollection CreateDataSource() { DataTable dt = new DataTable(); DataRow dr; dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32))); dt.Columns.Add(new DataColumn("StringValue", typeof(string))); dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double))); 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_Init(Object sender, EventArgs e) { // Empty DataGridColumnsCollection collection. ItemsGrid.Columns.Clear(); // Create dynamic columns to add to Columns collection. BoundColumn IntegerColumn = new BoundColumn(); BoundColumn StringColumn = new BoundColumn(); BoundColumn PriceColumn = new BoundColumn(); IntegerColumn.HeaderText="Item Number"; IntegerColumn.DataField="IntegerValue"; StringColumn.HeaderText="Item"; StringColumn.DataField="StringValue"; PriceColumn.HeaderText="Price"; PriceColumn.DataField="CurrencyValue"; // Add columns to Columns collection. ItemsGrid.Columns.Add(IntegerColumn); ItemsGrid.Columns.Add(StringColumn); ItemsGrid.Columns.Add(PriceColumn); } void Page_Load(Object sender, EventArgs e) { if (!IsPostBack) { // Load this data only once. ItemsGrid.DataSource= CreateDataSource(); ItemsGrid.DataBind(); } } </script> <head runat="server"> <title>DataGridColumnCollection Clear Example</title> </head> <body> <form id="form1" runat="server"> <h3>DataGridColumnCollection Clear Example</h3> <b>Product List</b> <asp:DataGrid id="ItemsGrid" BorderColor="black" BorderWidth="1" CellPadding="3" AutoGenerateColumns="false" runat="server"> <HeaderStyle BackColor="#00aaaa"> </HeaderStyle> <Columns> <asp:BoundColumn HeaderText="Item Number" DataField="IntegerValue"/> <asp:BoundColumn HeaderText="Item" DataField="StringValue"/> <asp:BoundColumn HeaderText="Price" DataField="CurrencyValue" DataFormatString="{0:c}"> <ItemStyle HorizontalAlign="right"> </ItemStyle> </asp:BoundColumn> </Columns> </asp:DataGrid> </form> </body> </html>
.NET Framework
Available since 1.1
Available since 1.1
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