from db to textbox

[Guest]

hey all,

when i pull a null value from a field in a database and try to put it in a
text box i get the following error:
Cast from type 'DBNull' to type 'String' is not valid.

How is this normally handled?

thanks,
rodchar

 

[Jonathan Allen]

It depends on how you are getting the database value, but this should work
for you.

If TypeOf value Is DBNull Then
textbox1.value = ""
Else
textbox1.value = value
End If

 

[ML]

Check for null before setting the value of the textbox.

isdbnull

 

[Herfried K. Wagner [MVP]]

when i pull a null value from a field in a database and try to put it in a
text box i get the following error:
Cast from type 'DBNull' to type 'String' is not valid.

'DBNull.Value.ToString' will return an empty string.

\\\
Me.TextBox1.Text = bla.ToString()
///

 

[ML]

Or you can always use the old empty string trick:
txtItem.Text = ds.Tables(0).Rows(0).Item("MyItem") & ""

 

[Cor Ligthert]

Rodchar,

How do you get a field direct from a database in a textbox, without
something as a dataset or a datareader.

When it is a dataset is normally binding used.

Cor

 

[Guest]

how about if you wanted to go the other way, if the user left the textbox
blank but you want to store null back in the database?

 

[ML]

Are you using bound controls or how are you updating the data?

 

[Guest]

using data adapter and dataset

Are you using bound controls or how are you updating the data?

 

[Cor Ligthert]

Rodchar,

Than use databinding, I have just made a little sample for that

http://groups-beta.google.com/group/microsoft.public.dotnet.languages.vb/msg/ccb320e72135ad3b?hl=en

I hope this helps,

Cor

 

[Guest]

thank you very much for everyone's help.