如何从gridview中的下拉列表中设置所选值？ [英] How to set the selected value from a dropdownlist in a gridview?

问题描述

您好



在我的网页上，当我从gridview编辑一行时，会使用下拉列表来选择一个值。现在默认选择的值是数据源提供的列表中的第一个值。

我遇到的问题是我无法为DDL设置所选值。



在我的vb代码中，我尝试按如下方式设置所选值：

Hello

On my webpage when I edit a row from the gridview, a dropdownlist is used to select a value. Now the default selected value is the first value from the list provided by the datasource.
The problem I have is that I can't set the selected value for the DDL.

In my vb code I try to set the selected value as follows:

Protected Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs) Handles GridView1.RowEditing
    Dim row As GridViewRow
    Dim lstdrop As DropDownList
    row = GridView1.Rows.Item(e.NewEditIndex())
    lstdrop = row.FindControl("DropDownListOwner")
    lstdrop.SelectedIndex = 3
End Sub

这里是我的asp代码的一部分：

Here is a part of my asp code:

<EditItemTemplate>
    <asp:DropDownList ID="DropDownListOwner" runat="server" DataSourceID="SqlDataOwner" DataValueField="User_name" DataTextField="User_name" AutoPostBack="true">
    </asp:DropDownList>
</EditItemTemplate>

单击行上的编辑时会出现以下错误：

System.NullReferenceException：未将对象引用设置为实例一个对象

When clicking edit on a row the following error occurs:
System.NullReferenceException: Object reference not set to an instance of an object

推荐答案

我认为这可能会有所帮助。



尝试将以下值添加到EditItemTemplate DropDownList项目。



SelectedValue ='<％＃Bind（value）％>'AppendDataBoundItems = true

I think this might help.

Try adding the following values to the EditItemTemplate DropDownList item.

SelectedValue='<%#Bind("value")%>' AppendDataBoundItems=true

不确定是否重要，但尝试删除 NewEditIndex

Not sure if it matters, but try removing the parenthesis on NewEditIndex

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