2 Gridview中的Dropdownlist导致错误：数据绑定方法（如Bind（））只能用于数据绑定控件的上下文中 [英] 2 Dropdownlists in Gridview cause error: Databinding methods such as Bind() can only be used in the context of a databound control

问题描述

虽然这似乎在之前讨论过，但我不能申请给予我的情况帮助：

我在编辑模板中有2个DropDownLists（DDL1，DDL2）一个GridView的绑定到一个SQLDataSource。 DDL2依赖于DDL1的选定值。

如果我将填充DropDownLists的SQLDataSources放置在顶层，即使我正确地解决了它（Gridview $ DDL1ControlID），也找不到DDL2的ControlParameter的ControlID。因此，我将SQLDataSources放置在Gridview的Edit Template中。现在，如果我在编辑模式下输入给定记录，则两个DropDownLists都会正确填充;如果我更改DDL1的索引，则DDL2不会自动更新，因为DDL2将AutoPostBack设置为false。一旦我将AutoPostBack设置为true，错误Eval（），XPath（）和Bind（）等数据绑定方法只能用于正在抛出。。

< asp：GridView runat =serverID =Gridview1
 DataSourceID =里程碑
 DataKeyNames =ID
 OnRowEditing = OnRowEditing
 OnRowDataBound =OnRowDataBoundMS
 OnSelectedIndexChanged =OnSelectedIndexChangedMS> 
 .... 
< asp：templatefield HeaderText =默认所有者组ItemStyle-Horizo​​ntalAlign =center> 
< ItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwnerGroup）％>'id =LabelDefaultOwnerGroupFont-Size =12pxWidth =50px/> ; 
< / ItemTemplate> 
< EditItemTemplate> 
< asp：SqlDataSource runat =serverid =OwnerGroupsProviderName =System.Data.SqlClient
 ConnectionString =Data Source = XXXXX
 SelectCommand =select function， 2 as ord 
 from Staff 
其中函数不为空
按函数分组
 union all 
选择'select'as function，0 as ord 
 union所有
选择'-----'作为函数，1作为ord 
按ord排序，函数> 
< / asp：SqlDataSource> 
< asp：DropDownList runat =serverid =DDOwnerGroupText ='<％＃Bind（DefaultOwnerGroup）％>'DataSourceID =OwnerGroupsDataTextField =functionDataValueField =function Font-Size =12pxWidth =80pxAutoPostBack =true/> 
< / EditItemTemplate> 
< / asp：templatefield> 
 
< asp：templatefield HeaderText =默认所有者ItemStyle-Horizo​​ntalAlign =center> 
< ItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwner）％>'id =LabelDefaultOwnerFont-Size =12pxWidth =50px/> ; 
< / ItemTemplate> 
< EditItemTemplate> 
  ConnectionString =Data Source = XXXXX
 SelectCommand =select Name， UserID 
 from Staff 
其中function = @OwnerGroup 
 union all 
选择Null作为Name，Null作为UserID 
按名称排序> 
< SelectParameters> 
< asp：ControlParameter ControlID =DDOwnerGroupPropertyName =SelectedValueName =OwnerGroupType =String/> 
< / SelectParameters> 
< / asp：SqlDataSource> 
< asp：DropDownList runat =serverid =DDOwnerText ='<％＃Bind（DefaultOwner）％>'Width =100pxDataSourceID =OwnerDataTextField =Name DataValueField =UserIDFont-Size =12px/> 
< / EditItemTemplate> 
< / asp：templatefield> 
  

解决方案

我在OnRowDataBound事件中绑定DropdownLists，如下所示：

 < asp：templatefield HeaderText =Default Owner GroupItemStyle-Horizo​​ntalAlign =center> 
< ItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwnerGroup）％>'id =LabelDefaultOwnerGroupFont-Size =12pxWidth =50px/> ; 
< / ItemTemplate> 
< EditItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwnerGroup）％>'id =LabelDefaultOwnerGroupEditVisible =false/> 
< asp：SqlDataSource runat =serverid =OwnerGroupsProviderName =System.Data.SqlClient
 ConnectionString =Data Source = XXXXX
 SelectCommand =... > 
< / asp：SqlDataSource> 
< asp：DropDownList runat =serverid =DDOwnerGroupDataSourceID =OwnerGroupsDataTextField =funcionDataValueField =funcionFont-Size =12pxWidth =80pxAutoPostBack =true /> 
< / EditItemTemplate> 
< / asp：templatefield> 
 
< asp：templatefield HeaderText =默认所有者ItemStyle-Horizo​​ntalAlign =center> 
< ItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwner）％>'id =LabelDefaultOwnerFont-Size =12pxWidth =50px/> ; 
< / ItemTemplate> 
< EditItemTemplate> 
< asp：Label runat =serverText ='<％＃Bind（DefaultOwner）％>'id =LabelDefaultOwnerEditVisible =false/> 
< asp：SqlDataSource runat =serverid =OwnerProviderName =System.Data.SqlClient
 ConnectionString =Data Source = XXXXX
 SelectCommand =... 。
< SelectParameters> 
< asp：ControlParameter ControlID =DDOwnerGroupPropertyName =SelectedValueName =OwnerGroupType =String/> 
< / SelectParameters> 
< / asp：SqlDataSource> 
 < / EditItemTemplate> 
< / asp：templatefield> 
 
 protected void OnRowDataBoundMS（object sender，GridViewRowEventArgs e）
 {
 if（e.RowType == DataControlRowType.DataRow）
 {
 if （（e.RowState& DataControlRowState.Edit）> 0）
 {
 DropDownList DDL1 = e.Row.FindControl（DDOwnerGroup）as DropDownList; 
 DropDownList DDL2 = e.Row.FindControl（DDOwner）as DropDownList; 
标签LBL1 = e.Row.FindControl（LabelDefaultOwnerGroupEdit）作为标签; 
标签LBL2 = e.Row.FindControl（LabelDefaultOwnerEdit）作为标签; 
 DDL1.SelectedValue = Convert.ToString（LBL1.Text）; 
 DDL2.DataBind（）; 
 DDL2.SelectedValue = Convert.ToString（LBL2.Text）; 
} 
} 
} 
  

Though this seems to be discussed before, I can't apply given help in my case:

I have 2 DropDownLists (DDL1, DDL2) inside the Edit Template of a Gridview, which is bound to a SQLDataSource. DDL2 depends on the selected value of DDL1.

If I place the SQLDataSources that populate the DropDownLists on the top level, the ControlID of DDL2's ControlParameter isn't found even though I address it correctly (Gridview$DDL1ControlID). Therefore I placed the SQLDataSources inside the Edit Template of the Gridview. Now both DropDownLists are populated correctly if I enter in Edit Mode for a given Record; if I change the Index for DDL1, DDL2 is not updated automatically, as DDL2 has AutoPostBack set to false. Once I set AutoPostBack to true, the error "Databinding methods such as Eval(), XPath(), and Bind() can only be used in the " is thrown.

    <asp:GridView runat="server" ID="Gridview1" 
                  DataSourceID="Milestones" 
                  DataKeyNames="ID"
                  OnRowEditing="OnRowEditing"
                  OnRowDataBound="OnRowDataBoundMS"
                  OnSelectedIndexChanged="OnSelectedIndexChangedMS">
....
            <asp:templatefield HeaderText="Default Owner Group" ItemStyle-HorizontalAlign="center">
            <ItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwnerGroup") %>' id="LabelDefaultOwnerGroup" Font-Size="12px" Width="50px"/>
            </ItemTemplate>
            <EditItemTemplate>
                <asp:SqlDataSource runat="server" id="OwnerGroups" ProviderName="System.Data.SqlClient"
                    ConnectionString="Data Source=XXXXX"    
                    SelectCommand="select function, 2 as ord
                                   from Staff
                                   where function is not null
                                   group by function
                                   union all
                                   select 'select' as function, 0 as ord
                                   union all
                                   select '-----' as function, 1 as ord
                                   order by ord, function">
                </asp:SqlDataSource>
                <asp:DropDownList runat="server" id="DDOwnerGroup" Text='<%# Bind("DefaultOwnerGroup") %>' DataSourceID="OwnerGroups" DataTextField="function" DataValueField="function" Font-Size="12px" Width="80px" AutoPostBack="true"/>
            </EditItemTemplate>
        </asp:templatefield>

        <asp:templatefield HeaderText="Default Owner" ItemStyle-HorizontalAlign="center">
            <ItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwner") %>' id="LabelDefaultOwner" Font-Size="12px" Width="50px"/>
            </ItemTemplate>
            <EditItemTemplate>
                <asp:SqlDataSource runat="server" id="Owner" ProviderName="System.Data.SqlClient" 
                    ConnectionString="Data Source=XXXXX"    
                    SelectCommand="select Name, UserID
                                   from Staff
                                   where function = @OwnerGroup
                                   union all
                                   select Null as Name, Null as UserID
                                   order by Name">
                <SelectParameters>
                    <asp:ControlParameter ControlID="DDOwnerGroup" PropertyName="SelectedValue" Name="OwnerGroup"  Type="String" />
                </SelectParameters>
                </asp:SqlDataSource>
                <asp:DropDownList runat="server" id="DDOwner" Text='<%# Bind("DefaultOwner") %>' Width="100px" DataSourceID="Owner" DataTextField="Name" DataValueField="UserID" Font-Size="12px"/>
            </EditItemTemplate>
        </asp:templatefield>

解决方案

I bind the DropdownLists in the OnRowDataBound Event like this:

            <asp:templatefield HeaderText="Default Owner Group" ItemStyle-HorizontalAlign="center">
            <ItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwnerGroup") %>' id="LabelDefaultOwnerGroup" Font-Size="12px" Width="50px"/>
            </ItemTemplate>
            <EditItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwnerGroup") %>' id="LabelDefaultOwnerGroupEdit" Visible="false"/>
                <asp:SqlDataSource runat="server" id="OwnerGroups" ProviderName="System.Data.SqlClient"
                    ConnectionString="Data Source=XXXXX"    
                    SelectCommand="...">
                </asp:SqlDataSource>
                <asp:DropDownList runat="server" id="DDOwnerGroup" DataSourceID="OwnerGroups" DataTextField="funcion" DataValueField="funcion" Font-Size="12px" Width="80px" AutoPostBack="true"/>
            </EditItemTemplate>
        </asp:templatefield>

        <asp:templatefield HeaderText="Default Owner" ItemStyle-HorizontalAlign="center">
            <ItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwner") %>' id="LabelDefaultOwner" Font-Size="12px" Width="50px"/>
            </ItemTemplate>
            <EditItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("DefaultOwner") %>' id="LabelDefaultOwnerEdit" Visible="false"/>
                <asp:SqlDataSource runat="server" id="Owner" ProviderName="System.Data.SqlClient" 
                    ConnectionString="Data Source=XXXXX"    
                    SelectCommand="...."
                <SelectParameters>
                    <asp:ControlParameter ControlID="DDOwnerGroup" PropertyName="SelectedValue" Name="OwnerGroup"  Type="String" />
                </SelectParameters>
                </asp:SqlDataSource>
                <asp:DropDownList runat="server" id="DDOwner" Width="100px" DataSourceID="Owner" DataTextField="Name" DataValueField="UserID" Font-Size="12px"/>
            </EditItemTemplate>
        </asp:templatefield>

protected void OnRowDataBoundMS(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        if ((e.Row.RowState & DataControlRowState.Edit) > 0)
        {
            DropDownList DDL1 = e.Row.FindControl("DDOwnerGroup") as DropDownList;
            DropDownList DDL2 = e.Row.FindControl("DDOwner") as DropDownList;
            Label LBL1 = e.Row.FindControl("LabelDefaultOwnerGroupEdit") as Label;
            Label LBL2 = e.Row.FindControl("LabelDefaultOwnerEdit") as Label;
            DDL1.SelectedValue = Convert.ToString(LBL1.Text);
            DDL2.DataBind();
            DDL2.SelectedValue = Convert.ToString(LBL2.Text);
        }
    }
}

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