c# - ASP .NET RowUpdating GridView问题

我在RowUpdating方法上遇到麻烦。我的GridView已连接到我们的本地SQL Server，并且我正在尝试更新数据。这是MSDN中RowUpdating方法的代码。

protected void TaskGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
        //Retrieve the table from the session object.
        DataTable dt = (DataTable)Session["TaskTable"];

        //Update the values.
        GridViewRow row = GridView1.Rows[e.RowIndex];
        dt.Rows[row.DataItemIndex]["Id"] = ((TextBox)(row.Cells[1].Controls[0])).Text;
        dt.Rows[row.DataItemIndex]["Description"] = ((TextBox)(row.Cells[2].Controls[0])).Text;
        dt.Rows[row.DataItemIndex]["IsComplete"] = ((CheckBox)(row.Cells[3].Controls[0])).Checked;

        //Reset the edit index.
        GridView1.EditIndex = -1;

        //Bind data to the GridView control.
        BindData();

}

我收到此错误：


  System.NullReferenceException：对象引用未设置为对象的实例。

最佳答案

尝试一次此代码。

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
    int id = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
    TextBox tname = (TextBox)row.FindControl("nam");
    TextBox tques = (TextBox)row.FindControl("que");
    MySqlCommand cmd = new MySqlCommand("update exam set name1=@name,ques=@ques where id = @id", con);
    cmd.Parameters.Add("@id", MySqlDbType.Int16).Value = id;
    cmd.Parameters.Add("@name", MySqlDbType.VarChar, 30).Value = tname.Text.Trim();
    cmd.Parameters.Add("@ques", MySqlDbType.VarChar,40).Value = tques.Text.Trim();
    con.Open();
    cmd.ExecuteNonQuery();
    GridView1.EditIndex = -1;
    bind();
}