這個問題反覆在論壇出現，其實這個問題在MSDN上早就有答案
1。英文版:Top Questions about the DataGrid Web Server Control(Mike Pope and Nikhil Kothari)
2。中文版:DataGrid Web 伺服器控制項的常見問題
可惜，論壇上的風氣不太好，你即使給了連接，真正去看的人大概並不多
訣竅是，如果動態添加了列的話，需要在下一次PostBack時，在LoadViewState或更早把這些列重新添加。原因是，在Page類遞歸調用LoadViewState時，會調用DataGrid的CreateChildControls，而DataGrid的(實際上是它的父類的實現)CreateChildControls會調用DataGrid的CreateControlHierarchy()方法。在其中，DataGrid會根據當前的列的數目構造DataGridItem裏的東西，然後從ViewState裏恢復原來的數據。如果你沒有重新添加你的動態列的話，你的動態列在PostBack後就會消失，更不用談觸發列裏的控件的事件了
檢驗你的動態控件在PostBack後是否還在的一個方法是，加一個按鈕看PostBack後的行爲
下面是一個簡單的測試
<html>
<body>
<form runat="server">
<asp:DataGrid id="DataGrid1" runat="server"
GridLines="Both" AutoGenerateColumns="false"
OnItemCommand="DataGrid1_ItemCommand">
<Columns>
<asp:ButtonColumn HeaderText="Static Button" Text="Click Me"
CommandName="Static"/>
<asp:TemplateColumn HeaderText="Data">
<ItemTemplate><%#Container.DataItem%></ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
<asp:Button id="btnAddAColumn" runat="server" Text="Add a column" OnClick="AddButtonColumn"/>
<asp:Button id="btnRefresh" runat="server" Text="Refresh" />
</form>
</body>
</html>
<script language="C#" runat="server">
void BindGrid()
{
DataGrid1.DataSource = new string[] {"a","b","c"};
DataGrid1.DataBind();
}
void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindGrid();
}
}
void DataGrid1_ItemCommand(Object sender, DataGridCommandEventArgs e)
{
Response.Write("ItemCommand is called<BR>");
LinkButton btn = e.CommandSource as LinkButton;
if (btn != null)
Response.Write(String.Format("{0} is clicked on row {1}", btn.CommandName, e.Item.ItemIndex));
}
//lifted from the original post
public void CreateGridColumn(DataGrid OperationDataGrid)
{
ButtonColumn NewButCol = new ButtonColumn() ;
NewButCol.Text = "編輯" ;
NewButCol.HeaderText = "操作" ;
NewButCol.CommandName = "Edit" ;
NewButCol.ButtonType = ButtonColumnType.LinkButton;
NewButCol.Visible = true ;
OperationDataGrid.Columns.Add(NewButCol) ;
//OperationDataGrid.Columns.AddAt(1,NewButCol) ;
}
bool ButtonAdded
{
get {
object o = ViewState["ButtonAdded"];
if (o == null)
return false;
else return (bool)o;
}
set { ViewState["ButtonAdded"] = value;}
}
void AddButtonColumn(object sender, EventArgs e)
{
CreateGridColumn(DataGrid1);
ButtonAdded = true;
BindGrid();
btnAddAColumn.Visible = false;
}
protected override void LoadViewState(object savedState)
{
base.LoadViewState(savedState);
//在這裏重新添加，假如已經添加的話
if (ButtonAdded)
CreateGridColumn(DataGrid1);
}
</script>