DataGrid中的DataBound DropDownList - 绑定顺序

I have a DataGrid that looks like this (slightly simplified here):

我有一个看起来像这样的DataGrid(这里稍微简化):

<asp:DataGrid ID="grdQuotas" runat="server" AutoGenerateColumns="False">
    <HeaderStyle CssClass="quotas-header" />
    <Columns>
        <asp:TemplateColumn>
            <HeaderTemplate>
                Max order level</HeaderTemplate>
            <ItemTemplate>
                <asp:DropDownList ID="ddlMaxOrderLevel" runat="server" DataSourceID="xdsOrderLevel"
                    DataTextField="Text" DataValueField="Value" SelectedValue='<%# Bind("MaxOrderLevel") %>'>
                </asp:DropDownList>
            </ItemTemplate>
        </asp:TemplateColumn>
    </Columns>
</asp:DataGrid>

<asp:XmlDataSource ID="xdsOrderLevel" runat="server" DataFile="~/App_Data/OrderLevels.xml">
</asp:XmlDataSource>

In my Page_Load event handler I am creating a DataTable containing default values and DataBinding it to the DataGrid.

在我的Page_Load事件处理程序中,我正在创建一个包含默认值的DataTable,并将它绑定到DataGrid。

The problem is that this is taking place before the DropDownList ddlMaxOrderLevel has been bound to its DataSource, so I get a runtime error telling me that the SelectedValue cannot be set.

问题是这是在DropDownList ddlMaxOrderLevel绑定到其DataSource之前发生的,因此我收到运行时错误,告诉我无法设置SelectedValue。

If ddlMaxOrderLevel was not in a DataGrid I could just call DataBind() on it. However I cannot do that in this scenario - since it is in an ItemTemplate.

如果ddlMaxOrderLevel不在DataGrid中,我可以在其上调用DataBind()。但是在这种情况下我不能这样做 - 因为它在ItemTemplate中。

Can anyone suggest a workaround or alternate approach?

任何人都可以提出解决方法或替代方法吗?

2 个解决方案

#1

Create another DataSource and bind it to the DataGrid. Where the SelectMethod would return the default values in a simple object.

创建另一个DataSource并将其绑定到DataGrid。 SelectMethod将返回简单对象中的默认值。

Then all the binding should happily work together.

然后所有绑定应该愉快地一起工作。

#2

You could do the Databinding of the DropDownlist in the Databound event of the DataGrid.

您可以在DataGrid的Databound事件中执行DropDownlist的数据绑定。

Edit: I will give you an example that i have tested:

编辑:我会给你一个我测试过的例子:

 protected void dg_ItemDataBound(object sender, DataGridItemEventArgs e)
    {
        if (e.Item.ItemType != ListItemType.Header && e.Item.ItemType != ListItemType.Footer)
        {
            DropDownList dl = (DropDownList)((DataGridItem)e.Item).FindControl("ddlMaxOrderLevel");

            dl.DataSource = levels;
            dl.DataBind();

            dl.SelectedValue = ((DataRowView)e.Item.DataItem)["number"].ToString();


        }

    }

#1