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

How do I avoid getting this error:

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

I am trying to get values from the database into a form for updating using a Datareader, SQL is set to allow nulls for certain fields as they are not required but the only way I can get the form to display is by adding a space in SQL.
Is there another way around this?
4/14/2004 8:18:45 AM 91979 articles. 2 followers. Follow

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Check if it is equal to DBNull.Value first and if it is, don't do the cast.
Stanley Tan

theSpoke Blog
4/14/2004 8:45:21 AM
Where in the code does it need to go?

I am using the following and it's the profile that isn't always required:

If dtrCompany.Read Then
company_name.Text = dtrCompany("company_name")
profile.Text = dtrCompany("profile")
End If
4/14/2004 9:04:50 AM
Well you want to check if the column data on the current row is null:

If dtrCompany("company_name") Is Not DBNull.Value Then
company_name.Text = dtrCompany("company_name")
End If

Stanley Tan

theSpoke Blog
4/15/2004 9:48:33 AM
Thanks - thats got it working
4/15/2004 10:17:25 AM

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