Gridview SelectedIndexChanged找不到单元格值

<asp:GridView ID="GridView1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="GridView1_SelectedIndexChanged">
    <!-- GridView的列定义 -->
</asp:GridView>

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
    // 获取选中行的索引
    int selectedIndex = GridView1.SelectedIndex;

    // 获取选中行的数据
    GridViewRow selectedRow = GridView1.Rows[selectedIndex];
    string cellValue = selectedRow.Cells[columnIndex].Text; // 获取指定列的单元格值

    // 进行相应的处理
    // ...
}

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" OnSelectedIndexChanged="GridView1_SelectedIndexChanged">
    <Columns>
        <!-- 列定义 -->
    </Columns>
</asp:GridView>

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
    int selectedIndex = GridView1.SelectedIndex;
    GridViewRow selectedRow = GridView1.Rows[selectedIndex];
    string cellValue = selectedRow.Cells[columnIndex].Text; // 确保columnIndex是正确的列索引

    // 进行相应的处理
    // ...
}

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
    int selectedIndex = GridView1.SelectedIndex;
    GridViewRow selectedRow = GridView1.Rows[selectedIndex];
    Label lblValue = selectedRow.FindControl("lblValue") as Label; // 根据控件ID获取模板列中的控件
    string cellValue = lblValue.Text;

    // 进行相应的处理
    // ...
}