c# - 如何在未选中复选框的情况下按删除按钮时在客户端显示错误消息

Question

当我没有在我的 gridview 中选择 checkbox 并按下 delete 按钮时，它显示错误“No Check box has been selected”但是在那之后当我选择 checkbox 并点击删除按钮它仍然显示错误不知道为什么？我没有使用任何数据库，我只使用 datatable 和 gridview。

这是删除按钮的代码

protected void DeleteButton_Click(object sender, EventArgs e)
{

    var dt = (DataTable)ViewState["CurrentData"];

    if (dt == null)
    {
        return;
    }
    List<DataRow> rowsToDelete = new List<DataRow>();
    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = (CheckBox)row.FindControl("CheckBox1");
        if (cb != null && cb.Checked)
        {
            row.Visible = false;

            //remove row by its index as it should GridViewRow index == DataRow index
            //it is not the best way but from your code I dont have information how your GridView looks
            dt.Rows.RemoveAt(row.RowIndex);

            GridView1.DataSource = dt;
            GridView1.DataBind();

            GridView2.DataSource = dt;
            GridView2.DataBind();

            ViewState["CurrentData"] = dt;
        }
        else
        {
            lblError.Visible = true;
        }
        for (int i = 0; i < rowsToDelete.Count; i++)
        {
            dt.Rows.Remove(rowsToDelete[i]);
        }
    }

Answer 1

请运行这段代码。

 protected void Button2_Click(object sender, EventArgs e)
 {
    var dt = (DataTable)ViewState["CurrentData"];

    if (dt == null)
    {
        return;
    }

    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = (CheckBox)row.FindControl("CheckBox2");
        if (cb != null && cb.Checked)
        {
            Label1.Visible = false;
            dt.Rows.RemoveAt(row.RowIndex);
            GridView1.DataSource = dt;
            GridView1.DataBind();

            GridView2.DataSource = dt;
            GridView2.DataBind();

            ViewState["CurrentData"] = dt;
        }
        else if (cb.Checked == false)
        {
            Label1.Visible = true;
        }
    }

}