使用带有布尔值的联合查询并将其设置为复选框asp时出错。网

我有一个ASP。NET页面,该页面具有带复选框控件的gridview,该控件绑定到查询(简化版本如下):

<asp:SqlDataSource ID="gvPhonesDataSource" runat="server" OnInserted="gvPhonesDataSource_Inserted"
    ConnectionString="<%$ ConnectionStrings:ConnString %>" 
    SelectCommand="SELECT p.[CustomerPhoneID]
                ,p.[IsActive]
            FROM [dbo].[CustomerPhones] p
            WHERE p.CustomerContactID = @CustomerContactID
            UNION SELECT -1 AS CustomerPhoneID, 0 AS [IsActive]"
    <SelectParameters>
        <asp:ControlParameter Name="CustomerContactID" Type="Int32" ControlID="contactid" PropertyName="Text" />
    </SelectParameters>
</asp:SqlDataSource>

<asp:gridview ID="gvPhones" runat="server" DataSourceID="gvPhonesDataSource"
    AutoGenerateColumns="False" DataKeyNames="CustomerPhoneID" 
    CssClass="searchresultsgrid" ShowFooter="True" OnRowCommand="gvPhones_RowCommand" AllowSorting="True"
    OnRowDataBound="gvPhones_RowDataBound">
    <Columns>
        <asp:BoundField DataField="CustomerPhoneID" InsertVisible="false" ReadOnly="true" Visible="False" />

        <asp:TemplateField HeaderText="Active?" SortExpression="IsActive">
            <FooterTemplate>
                <asp:CheckBox runat="server" Checked='<%# Bind("IsActive") %>' ID="chkPhoneIsActive"></asp:CheckBox>
            </FooterTemplate>
            <EditItemTemplate>
                <asp:CheckBox runat="server" Checked='<%# Bind("IsActive") %>' ID="chkPhoneIsActive"></asp:CheckBox>
            </EditItemTemplate>
            <ItemTemplate>
                <asp:Label runat="server" Text='<%# Bind("IsActive") %>' ID="lblPhoneIsActive"></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>


        <asp:TemplateField ShowHeader="False">
            <EditItemTemplate>
                <asp:LinkButton runat="server" Text="Update" CommandName="Update" CausesValidation="True" ID="PhoneUpdate"></asp:LinkButton>&nbsp;<asp:LinkButton runat="server" Text="Cancel" CommandName="Cancel" CausesValidation="False" ID="PhoneEditCancel"></asp:LinkButton>
            </EditItemTemplate>
            <ItemTemplate>
                <asp:LinkButton runat="server" Text="Edit" CommandName="Edit" CausesValidation="False" ID="PhoneEdit"></asp:LinkButton>&nbsp;<asp:LinkButton runat="server" Text="Delete" CommandName="Delete" CausesValidation="False" ID="PhoneDelete"></asp:LinkButton>
            </ItemTemplate>
            <FooterTemplate>
                <asp:LinkButton runat="server" Text="Save New Phone" CommandName="FooterInsert" CausesValidation="True" ID="PhoneInsert"></asp:LinkButton>
            </FooterTemplate>
        </asp:TemplateField>
    </Columns>
</asp:gridview>

一切正常,SqlDataSource中的SELECT命令中没有UNION SELECT。但是,当我输入UNION SELECT时,gridview的IsActive列中的值不再列为“是”或“否”,而是开始列为“1”或“0”,当我尝试进入编辑(尝试将IsActive绑定到复选框)时,我得到以下错误:

Exception Details: System.InvalidCastException: Specified cast is not valid.

Source Error: 

Line 143:                            </FooterTemplate>
Line 144:                            <EditItemTemplate>
Line 145:                                <asp:CheckBox runat="server" Checked='<%# Bind("IsActive") %>' ID="chkPhoneIsActive"></asp:CheckBox>
Line 146:                            </EditItemTemplate>
Line 147:                            <ItemTemplate>

Source File: ...\ContactEdit.aspx    Line: 145 

我怀疑问题在查询中。。。UNION导致绑定的IsActive列以字符串而不是布尔值的形式返回(无论如何,编译器都是这么认为的)。如何修复并集,使IsActive继续被视为布尔值?

仅供参考,表(SQL Server 2014)的相关部分如下:

CREATE TABLE [dbo].[CustomerPhones](
    [CustomerPhoneID] [int] IDENTITY(1,1) NOT NULL,
    [IsActive] [bit] NOT NULL CONSTRAINT [DF_CustomerPhones_IsActive]  DEFAULT ((1)),
 CONSTRAINT [PK_CustomerPhones] PRIMARY KEY CLUSTERED 
(
    [CustomerPhoneID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

非常感谢!