DBNull error

[briancostea]

i just started getting the following error this week ... it was working fine for about 3 weeks until yesterday. any help would be greatly appreciated.

error:
System.InvalidCastException: Conversion from type 'DBNull' to type 'String' is not valid.


code:
txtCarAg.Attributes.Add("value", IIF(ObjDataReader("car") is dbNull.Value, "", replace(ObjDataReader("car"), "*", "'")))

thanks - brian

 

[DotNetGnat]

If the field is null, the cast will fail. So try something like this:

If Not (ObjDataReader("car") Is DbNull.Value) Then
'do something
Else
'do something else
End If

-DNG

 

[briancostea]

i believe that is what i am doing with the iif() statment. it should return "" if the field is null.

 

[dvannoy]

When inserting your records it's a good idea to check for null values. your not getting this error using the data reader are you? The datareader is one way only(Forward only)

When I use a datareader i always do the following

txt.text = reader("FieldName") & ""

Are you trying to update the DB when you receive this error?

Let the datareader populate your controls, then check for null values when updating.

 

[lpatnaik]

Use the following:

txtCarAg.Attributes.Add("value", IIF(ObjDataReader("car") is dbNull.Value, "", replace(ObjDataReader("car").ToString(), "*", "'")))

I am sure it will work.

 

[briancostea]

same error, but thanks for taking a look see.