Question

I have Gridview which uses this SqlDataSource as DataSource

<asp:SqlDataSource ID="dsMetal" runat="server" 
        ConnectionString="<%$ConnectionStrings:connStr%>"
        SelectCommand="select MetalName, MetalID, IsAvailable from Metal Where IsDeleted = 0" FilterExpression="IsAvailable like '%{0}%'>
   <asp:ControlParameter Name="IsAvailable" ControlID="ddlIsMetalAvailable" PropertyName="SelectedValue" Type="Boolean" />
</asp:SqlDataSource>

And this is my DropDownList:

<asp:DropDownList ID="ddlIsMetalAvailable" DataValueField="IsAvailable"
     AppendDataBoundItems="true" AutoPostBack="true" runat="server" Width="150">
                        <asp:ListItem Text="True"  Value="True" />
                        <asp:ListItem Text="False"  Value="False" />
</asp:DropDownList>

I am getting an error:

Cannot perform ‘Like’ operation on System.Boolean and System.String.

I have also tried this filter expression but it doesn’t helps me:

FilterExpression="Convert(IsAvailable, 'System.Boolean') like '%{0}%'

Answer 1

Just read the error message – it clearly says what’s wrong:

Cannot perform ‘Like’ operation on System.Boolean and System.String.

You cannot use LIKE with a boolean value – you need to use an exact match.

So change your markup to be:

<asp:SqlDataSource ID="dsMetal" runat="server" 
        ConnectionString="<%$ConnectionStrings:connStr%>"
        SelectCommand="select MetalName, MetalID, IsAvailable from Metal Where IsDeleted = 0" 
        FilterExpression="IsAvailable = {0}'>   <=== HERE - use = {0} instead of LIKE
   <FilterParameters>
      <asp:ControlParameter Name="IsAvailable" ControlID="ddlIsMetalAvailable" 
                            PropertyName="SelectedValue" Type="Boolean" />
   </FilterParameters>
</asp:SqlDataSource>

With this change, things should work just fine.