Question

我有一个带有asp.net按钮的gridview，它调用C＃方法根据gridview行中的某些数据更新数据库。该方法获取rowindex和值以更新数据记录。然后我想隐藏该行的按钮。我使用下面显示的代码：

protected void AddJacket_Click(object sender, EventArgs e)
    {
        //Determine the RowIndex of the Row whose Button was clicked.
        int rowIndex = ((sender as Button).NamingContainer as GridViewRow).RowIndex;

        //Get the value of column from the DataKeys using the RowIndex.
        int id1 = Convert.ToInt32(GridViewSubjectList.DataKeys[rowIndex].Values[0]);
        int id2 = Convert.ToInt32(GridViewSubjectList.DataKeys[rowIndex].Values[1]);

        using (CADWEntities db = new CADWEntities())
        {
            var results = db.Subjects.SingleOrDefault(uu => uu.SubjectId == id1);
            results.JacketNumber = Convert.ToString(id2);
            db.SaveChanges();

        }

        //Hide the button after being click
        Button Button = GridViewSubjectList.SelectedRow.Cells[0].FindControl("btnAddJacket") as Button;
        Button.Enabled = false;
        Button.Visible = false;
    }

我在隐藏按钮的第一行代码中收到此错误消息{“对象引用未设置为对象的实例。”}。

如果我对方法OnSelectedIndexChange使用相同的代码并将按钮更改为LinkButton，则隐藏链接的代码可以正常工作，但更新数据库的代码将失败。

如何让这段代码一起工作？

由于

Answer 1

您只需将sender投射到Control并将其设为visible = false

protected void AddJacket_Click(object sender, EventArgs e)
{
    //Determine the RowIndex of the Row whose Button was clicked.
    int rowIndex = ((sender as Button).NamingContainer as GridViewRow).RowIndex;

    //Get the value of column from the DataKeys using the RowIndex.
    int id1 = Convert.ToInt32(GridViewSubjectList.DataKeys[rowIndex].Values[0]);
    int id2 = Convert.ToInt32(GridViewSubjectList.DataKeys[rowIndex].Values[1]);

    using (CADWEntities db = new CADWEntities())
    {
        var results = db.Subjects.SingleOrDefault(uu => uu.SubjectId == id1);
        results.JacketNumber = Convert.ToString(id2);
        db.SaveChanges();

    }

    //Hide the button after being click
    (sender as Control).Visible = false;
}

注意：sender是引发事件的控件，同样，我将sender转换为Control，因为无论它是{{1} }}，Button等适用于具有LinkButton属性的任何Control

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