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DataGridColumnCollection.Item[Int32] Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Gets a DataGridColumn-derived column object from the DataGridColumnCollection collection at the specified index.

C# 
[System.ComponentModel.Browsable(false)]
public System.Web.UI.WebControls.DataGridColumn this[int index] { get; }

Parameters

index
Int32

The index of the DataGridColumn-derived column in the DataGridColumnCollection to retrieve.

Property Value

DataGridColumn

A DataGridColumn-derived column in the DataGridColumnCollection at the specified index.

Attributes
BrowsableAttribute

Examples

The following code example demonstrates how to use the indexer to get a DataGridColumn-derived column object from the DataGridColumnCollection collection. The heading text from the DataGridColumn-derived column object is then displayed on the Web page for each item in the collection.

ASP.NET (C#) 
<%@ 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">

   DataTable Cart = new DataTable();
   DataView CartView;   

   void Page_Load(Object sender, EventArgs e) 
   {
      DataRow dr;

      if (Session["ShoppingCart"] == null) 
      {       

         Cart.Columns.Add(new DataColumn("Qty", typeof(String)));
         Cart.Columns.Add(new DataColumn("Item", typeof(String)));
         Cart.Columns.Add(new DataColumn("Price", typeof(String)));
         Session["ShoppingCart"] = Cart;
            
         // Create sample data.
         for (int i = 1; i <= 4; i++) 
         {
            dr = Cart.NewRow();
            if (i % 2 != 0)
               dr[0] = "2";
            else
               dr[0] = "1";
            dr[1] = "Item " + i.ToString();
            dr[2] = (1.23 * (i + 1)).ToString();
            Cart.Rows.Add(dr);
         }
      }
      else
         Cart = (DataTable)Session["ShoppingCart"];          

      CartView = new DataView(Cart);
      CartView.Sort="Item";

      if (!IsPostBack)
         BindGrid(); 
                  
   }

   void MyDataGrid_Edit(Object sender, DataGridCommandEventArgs e) 
   {
      MyDataGrid.EditItemIndex = e.Item.ItemIndex;
      BindGrid();
   }

   void MyDataGrid_Cancel(Object sender, DataGridCommandEventArgs e) 
   {
      MyDataGrid.EditItemIndex = -1;
      BindGrid();
   }

   void MyDataGrid_Update(Object sender, DataGridCommandEventArgs e) 
   {
      // For bound columns, the edited value is stored in a TextBox.
      // The TextBox is the 0th element in the column's cell.
      TextBox qtyText = (TextBox)e.Item.Cells[2].Controls[0];
      TextBox priceText = (TextBox)e.Item.Cells[3].Controls[0];

      String item = e.Item.Cells[1].Text;
      String qty = qtyText.Text;
      String price = priceText.Text;
       
      DataRow dr;

      // With a database, use an update command to update the data. Because 
      // the data source in this example is an in-memory DataTable, delete the 
      // old row and replace it with a new one.

      // Remove old entry.
      CartView.RowFilter = "Item='" + item + "'";
      if (CartView.Count > 0)
         CartView.Delete(0);
      CartView.RowFilter = "";

      // Add new entry.
      dr = Cart.NewRow();
      dr[0] = qty;
      dr[1] = item;
      dr[2] = price;
      Cart.Rows.Add(dr);

      MyDataGrid.EditItemIndex = -1;
      BindGrid();
   }

   void Button_Click(Object sender, EventArgs e) 
   {      
      Label1.Text = "Header Text for each column: <br />";

      for (int i = 0; i < MyDataGrid.Columns.Count; i++)
      {
         Label1.Text += "<br />" + MyDataGrid.Columns[i].HeaderText;
      }
   }

   void BindGrid() 
   {
      MyDataGrid.DataSource = CartView;
      MyDataGrid.DataBind();
   }

</script>

<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body style="font: 10pt verdana">

   <form id="form1" runat="server">

      <asp:DataGrid id="MyDataGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           Font-Names="Verdana"
           Font-Size="8pt"
           HeaderStyle-BackColor="#aaaadd"
           OnEditCommand="MyDataGrid_Edit"
           OnCancelCommand="MyDataGrid_Cancel"
           OnUpdateCommand="MyDataGrid_Update"
           AutoGenerateColumns="false">

         <Columns>

            <asp:EditCommandColumn
                 EditText="Edit"
                 CancelText="Cancel"
                 UpdateText="Update"
                 ItemStyle-Wrap="false"
                 HeaderText="Edit Command Column"
                 HeaderStyle-Wrap="false"/>

            <asp:BoundColumn HeaderText="Item" 
                 ReadOnly="true" 
                 DataField="Item"/>

            <asp:BoundColumn HeaderText="Quantity" 
                 DataField="Qty"/>

            <asp:BoundColumn HeaderText="Price" 
                 DataField="Price"/>

         </Columns>

      </asp:DataGrid>

      <br /><br />

      <asp:Button id="Button1"
           Text="Display Header Text for Columns"
           OnClick="Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label id="Label1"
           runat="server"/>      

   </form>

</body>
</html>

Remarks

Use this indexer to get a DataGridColumn-derived column object from the DataGridColumnCollection collection at the specified index using array notation.

Applies to

Product Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also