Test if a value exists in a DataTable Column?

[MattB]

I know I can use dataviews and more looping to do this, but I'm
wondering if there's a more elegant or more concise way to do this.

I've got two DataTables with a column called guest_no. I'd love to be
able to use something like the .IndexOf method of arrays and bound
controls. Somehting like:

Dim r as DataRow
For Each r in DataTable2.Rows
If DataTable1.Colu mns("guest_no") .IndexOf(r("gue st_no")) <> -1
'record exists
'do something
Else
'record doesn't exist
'do something else
End If
End For

Is there anything like this? Obviously, the code above doesn't work.

Thanks,
Matt

[Marina]

A column in a datatable is like a column in a table in your database. You
wouldn't expect the column definition to just have a value, would you? No.
You would expect a column (cell) in a particular row to have a value. Same
goes here.

Asking a column to have a value doesn't make sense semantically.

Something like:

DataTable1.Rows (0)("guest_no")

makes sense. That asks for the value of the guest_no column in the first
row.

Remember that this returns an Object, turn Option Strict On, and then type
this to the correct type - in your case a string.

"MattB" <so********@yah oo.com> wrote in message
news:3t******** ****@individual .net...

I know I can use dataviews and more looping to do this, but I'm wondering
if there's a more elegant or more concise way to do this.

I've got two DataTables with a column called guest_no. I'd love to be able
to use something like the .IndexOf method of arrays and bound controls.
Somehting like:

Dim r as DataRow
For Each r in DataTable2.Rows
If DataTable1.Colu mns("guest_no") .IndexOf(r("gue st_no")) <> -1
'record exists
'do something
Else
'record doesn't exist
'do something else
End If
End For

Is there anything like this? Obviously, the code above doesn't work.

Thanks,
Matt

[MattB]

Yes, I know. I was just looking for a shortcut for more concise code.
Something like how I can have an array and use the IndexOf method to
quickly know if a values exists and in what element if it does without
having to loop through the array, testing each element explicitly.

Thanks for the reply,
Matt

Marina wrote:

A column in a datatable is like a column in a table in your database. You
wouldn't expect the column definition to just have a value, would you? No.
You would expect a column (cell) in a particular row to have a value. Same
goes here.

Asking a column to have a value doesn't make sense semantically.

Something like:

DataTable1.Rows (0)("guest_no")

makes sense. That asks for the value of the guest_no column in the first
row.

Remember that this returns an Object, turn Option Strict On, and then type
this to the correct type - in your case a string.

"MattB" <so********@yah oo.com> wrote in message
news:3t******** ****@individual .net...

I know I can use dataviews and more looping to do this, but I'm wondering
if there's a more elegant or more concise way to do this.

I've got two DataTables with a column called guest_no. I'd love to be able
to use something like the .IndexOf method of arrays and bound controls.
Somehting like:

Dim r as DataRow
For Each r in DataTable2.Rows
If DataTable1.Colu mns("guest_no") .IndexOf(r("gue st_no")) <> -1
'record exists
'do something
Else
'record doesn't exist
'do something else
End If
End For

Is there anything like this? Obviously, the code above doesn't work.

Thanks,
Matt