Cast from type 'DBNull' to type 'String' is not valid

Hi,

 I have an old website and old database (SQL 2000).  I add new column "ImageURL' to database, so all data (several thousand items) are "NULL" (actually is dbNull) under this column.

 In searchResult.aspx page, inside the datagrid, I add a colummn call "Image"

<code>

<asp:datagrid id="dgSearchResult" runat="server">
<Columns>
<asp:TemplateColumn HeaderText="Image" ItemStyle-Width="55px" ItemStyle-HorizontalAlign=Center>
 <ItemTemplate>
 <asp:Image ID=ThumbImage Width=50 Height=35 ImageUrl=<%# NewURL(DataBinder.Eval(Container.DataItem, "ImageURL"))%> runat=server></asp:Image></a>
 </ItemTemplate>
 </asp:TemplateColumn>
</Columns>
</asp:datagrid>

</code>

 

Then I add a function to codebehind:

<code>

Function NewURL(ByVal URL As String)  
        Dim ShowURL As String
        If IsDBNull(URL) Then
            ShowURL = "images\Empty.gif"
        Else
            ShowURL = URL
        End If
        Return ShowURL
End Function

</code>

When I run the program, error happened and error was "Cast from type 'DBNull' to type 'String' is not valid".

I try to use (ByVal URL As SqlDbType), then the error was: Cast from type 'DBNull' to type 'Integer' is not valid

How to solve this problem?  Please help!

Thanks.

 

 

 

0
mylin
7/16/2007 11:53:19 PM
asp.net.presentation-controls 72751 articles. 3 followers. Follow

1 Replies
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Convert your function that accepts object 

Function NewURL(ByVal URL As Object)  
        Dim ShowURL As String
        If URL is Nothing OrElse IsDBNull(URL) Then
            ShowURL = "images\Empty.gif"
        Else
            ShowURL = URL.ToString()
        End If
        Return ShowURL
End Function


Raghu
(MCSD.NET, MCAD.NET, MCDBA)
[Don't forget to click on Mark as answer on the post that helped you ]
0
rmaiya
7/17/2007 12:05:20 AM
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