在GridView中设置DropDownList的选定值

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
    <Columns>
        <asp:TemplateField HeaderText="Options">
            <ItemTemplate>
                <asp:DropDownList ID="DropDownList1" runat="server">
                    <!-- 添加选项 -->
                    <asp:ListItem Text="Option 1" Value="1"></asp:ListItem>
                    <asp:ListItem Text="Option 2" Value="2"></asp:ListItem>
                    <asp:ListItem Text="Option 3" Value="3"></asp:ListItem>
                </asp:DropDownList>
            </ItemTemplate>
        </asp:TemplateField>
        <!-- 其他列 -->
    </Columns>
</asp:GridView>

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList ddl = (DropDownList)e.Row.FindControl("DropDownList1");
        // 设置选定值
        ddl.SelectedValue = DataBinder.Eval(e.Row.DataItem, "ColumnName").ToString();
    }
}

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowDataBound="GridView1_RowDataBound">
    <!-- GridView的定义 -->
</asp:GridView>