Question

我有包含Label的DetailsView Template控件。

<ItemTemplate>
<asp:Label ID="Label_AssemblyPart" runat="server" Text='<%# Bind("AssemblyPart") %>'></asp:Label>
</ItemTemplate>

如果我将SQLDataSource绑定到ASP标记中的DetailsView，则DetailsView1_OnDataBound例程不会触发Page_Load，这是正确的行为。

        <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
        ConflictDetection="CompareAllValues" ConnectionString="<%$ ConnectionStrings:inventory_v2ConnectionString %>"
        SelectCommand="SELECT   Part_Catalog.ID,
                                Part_Catalog.OEMPartCode,
                                Part_Catalog.PartCode2,
                                Part_Catalog.UsedByOEM,
                                Models_OEMs.Manufacturer AS JoinedUsedByOEM,
                                Part_Catalog.ItemType,                                    
                                Part_ItemTypes.Type AS JoinedItemType, 
                                Part_Catalog.GroupType,
                                Part_Groups.GroupType AS GroupTypeText,
                                Part_Groups.GroupType + ' - ' + Part_Groups.GroupName AS JoinedGroupType,                                    
                                Part_Catalog.PartDesc,
                                Part_Catalog.PartComment,
                                Part_Catalog.PartCount, 
                                Part_Catalog.PartMin,
                                Part_Catalog.PartActive,
                                Part_Catalog.MFRPartNumber,
                                Part_Catalog.PartCapacity,
                                Part_Catalog.PreTurnRequired,
                                Part_Catalog.AssemblyPart,                                     
                                Part_Catalog.PartImage,
                                Part_Catalog.PartImage2,
                                Part_Catalog.NonInventoryPart,
                                Part_Catalog.CreatedByUser,
                                Part_Catalog.LastModifiedDate                                    
                           FROM Part_Catalog INNER JOIN
                                 Models_OEMs ON Part_Catalog.UsedByOEM = Models_OEMs.ID INNER JOIN
                                 Part_Groups ON Part_Catalog.GroupType = Part_Groups.ID INNER JOIN
                                 Part_ItemTypes ON Part_Catalog.ItemType = Part_ItemTypes.ID                                     
                          WHERE (Part_Catalog.ID = @ID)"
        OnUpdating="SqlDataSource2_Updating"
        DeleteCommand="DELETE FROM [Part_Catalog] WHERE [ID] = @ID"
        InsertCommand=""
        UpdateCommand="dbo.Procedure_UpdatePartCatalog" UpdateCommandType="StoredProcedure">

        <SelectParameters>
            <asp:ControlParameter ControlID="GridView1" Name="ID" PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>

如果我在Page_Load中的代码中为基于标记的数据源设置配置字符串：

        if (GridView1.SelectedIndex != -1)
        {
            DetailsView1.Visible = true;
            DetailsView1.Focus();
            SqlDataSource2.ConnectionString = ConfigurationManager.ConnectionStrings[conString].ConnectionString;
        }

DetailsView1_OnDataBound事件在查看Label_AssemblyPart.Text时会触发并返回null错误。

DetailsView_OnDataBound事件根本不应该触发，因为在第一个page_load上，DetailsView不应该绑定任何数据。有一个Gridview在GridView_SelectedIndex_Changed事件上加载DetailsView，并且只在PostBack上发生。

看起来将连接字符串分配给DataSource的行为导致了数据绑定。

Answer 1

修复程序结果是为每个EditItemTemplate控件设置一个Onload事件，该控件将设置SQLDataSource连接字符串。

        <EditItemTemplate>
<asp:DropDownList ID="DDL_ItemType_E" runat="server"
DataSourceID="SQL_DS_ItemType_E" DataTextField="Type" DataValueField="ItemTypeID"
Height="25px" Width="150px" AutoPostBack="True"
OnDataBound="DDL_ItemType_E_DataBinding" OnLoad="DDL_ItemType_E_Load" SelectedValue='<%# Bind("ItemType") %>'>
</asp:DropDownList>
<asp:SqlDataSource ID="SQL_DS_ItemType_E" runat="server"                                        
SelectCommand="SELECT [ID] AS ItemTypeID, [Type] FROM [Part_ItemTypes]"></asp:SqlDataSource>
</EditItemTemplate>



        protected void DDL_ItemType_E_Load(object sender, EventArgs e)
{
    SqlDataSource SQL_DS_ItemType_E = (SqlDataSource)DetailsView1.FindControl("SQL_DS_ItemType_E");
    SQL_DS_ItemType_E.ConnectionString = ConfigurationManager.ConnectionStrings[Master.conString].ConnectionString;
}

更改CS中SQL数据连接的配置字符串时的奇怪行为

1 个答案: