1. 通过获取传入事件对象的行（Item 对象）的 ItemIndex 属性确定哪个 DataGrid 行已被更新。然后使用该索引值从网格的 DataKeys 集合中获取对应的值。

   ' Visual Basic
       Dim key As String = DataGrid1.DataKeys(e.Item.ItemIndex).ToString()
       // C#
       string key = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();

2. 从 DataGrid 行中获取更改的值。若要完成该操作，请：
   1. 从传入事件对象的项的 Cells 集合中获取适当的单元格（从零开始的）。例如，网格中最左边一列为 Cells(0)。
   2. 对于每个单元格，获取其 Controls 集合，它包含显示在该单元格中的所有元素。
   3. 从该集合中获取且仅获取第一个控件，在本例中为 TextBox 控件。若要获取 TextBox，声明一个类型 TextBox 的局部变量，并将 Controls 集合中的对象分配给它。
   4. 获取 TextBox 控件的值（其 Text 属性）。
      下面的示例显示如何执行这些步骤。

      ' Visual Basic
              Dim categoryName, categoryDescription As String
              Dim tb As TextBox
              tb = CType(e.Item.Cells(2).Controls(0), TextBox)
              categoryName = tb.Text
              tb = CType(e.Item.Cells(3).Controls(0), TextBox)
              categoryDescription = tb.Text
              // C#
              string categoryName;
              string categoryDescription;
              TextBox tb;
              tb = (TextBox) e.Item.Cells[2].Controls[0];
              categoryName = tb.Text;
              tb = (TextBox) e.Item.Cells[3].Controls[0];
              categoryDescription = tb.Text

3. 在数据表中查找对应的行。类型化的 dsCategories 数据集包含一个特殊的 FindBy 方法（在本例中为 FindByCategoryID 方法），该方法通过行的主键定位行，并返回一个对行的引用。创建类型化数据行的变量并调用该方法：

   ' Visual Basic
       Dim r As dsCategories.CategoriesRow
       r = DsCategories1.Categories.FindByCategoryID(key)
       // C#
       dsCategories.CategoriesRow r;
       r = dsCategories1.Categories.FindByCategoryID(int.Parse(key));

4. 通过更改您在第三步所在行中的值更新该行，如下面的示例所示：

   ' Visual Basic
       r.CategoryName = categoryName
       r.Description = categoryDescription
       // C#
       r.CategoryName = categoryName;
       r.Description = categoryDescription;

5. 通过调用数据适配器的 Update 方法将更改从数据集发送到数据库：

   ' Visual Basic
       SqlDataAdapter1.Update(DsCategories1)
       DataGrid1.DataBind()
       // C#
       sqlDataAdapter1.Update(dsCategories1);
       DataGrid1.DataBind();

6. 将网格中的当前行切换出编辑模式。

   ' Visual Basic
       DataGrid1.EditItemIndex = -1
       // C#
       DataGrid1.EditItemIndex = -1;

7. 数据绑定 DataGrid 控件：

   ' Visual Basic
       DataGrid1.DataBind()
       // C#
       DataGrid1.DataBind();

提示   一定要改写先前创建的主干事件处理程序，否则将有两个方法具有相同的名称和签名。

' Visual Basic
Private Sub DataGrid1_UpdateCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles DataGrid1.UpdateCommand
Dim categoryName, categoryDescription As String
' Gets the value of the key field of the row being updated
Dim key As String = DataGrid1.DataKeys(e.Item.ItemIndex).ToString()
' Gets get the value of the controls (textboxes) that the user
' updated. The DataGrid columns are exposed as the Cells collection.
' Each cell has a collection of controls. In this case, there is only one
' control in each cell -- a TextBox control. To get its value,
' you copy the TextBox to a local instance (which requires casting)
' and extract its Text property.
'
' The first column -- Cells(0) -- contains the Update and Cancel buttons.
Dim tb As TextBox
' Gets the value the TextBox control in the third column
tb = CType(e.Item.Cells(2).Controls(0), TextBox)
categoryName = tb.Text
' Gets the value the TextBox control in the fourth column
tb = CType(e.Item.Cells(3).Controls(0), TextBox)
categoryDescription = tb.Text
' Finds the row in the dataset table that matches the
' one the user updated in the grid. This example uses a
' special Find method defined for the typed dataset, which
' returns a reference to the row.
Dim r As dsCategories.CategoriesRow
r = DsCategories1.Categories.FindByCategoryID(key)
' Updates the dataset table.
r.CategoryName = categoryName
r.Description = categoryDescription
' Calls a SQL statement to update the database from the dataset
SqlDataAdapter1.Update(DsCategories1)
' Takes the DataGrid row out of editing mode
DataGrid1.EditItemIndex = -1
' Refreshes the grid
DataGrid1.DataBind()
End Sub
// C#
private void DataGrid1_UpdateCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
string categoryName, categoryDescription;
// Gets the value of the key field of the row being updated
string key = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
// Gets get the value of the controls (textboxes) that the user
// updated. The DataGrid columns are exposed as the Cells collection.
// Each cell has a collection of controls. In this case, there is only    one
// control in each cell -- a TextBox control. To get its value,
// you copy the TextBox to a local instance (which requires casting)
// and extract its Text property.
//
// The first column -- Cells(0) -- contains the Update and Cancel buttons.
TextBox tb;
// Gets the value the TextBox control in the third column
tb = (TextBox)(e.Item.Cells[2].Controls[0]);
categoryName = tb.Text;
// Gets the value the TextBox control in the fourth column
tb = (TextBox)(e.Item.Cells[3].Controls[0]);
categoryDescription = tb.Text;
// Finds the row in the dataset table that matches the
// one the user updated in the grid. This example uses a
// special Find method defined for the typed dataset, which
// returns a reference to the row.
dsCategories.CategoriesRow r;
r = dsCategories1.Categories.FindByCategoryID(int.Parse(key));
// Updates the dataset table.
r.CategoryName = categoryName;
r.Description = categoryDescription;
// Calls a SQL statement to update the database from the dataset
sqlDataAdapter1.Update(dsCategories1);
// Takes the DataGrid row out of editing mode
DataGrid1.EditItemIndex = -1;
// Refreshes the grid
DataGrid1.DataBind();
}

测试