SqlDataAdapter.Fill(DataGridView.DataSource) duplicates all rows

Question

Simple question:

When I call SqlDataAdapter.Fill(DataGridView.DataSource) the second time after initially creating first Data it does not update the contain

Answer 1

From MSDN:

You can use the Fill method multiple times on the same DataTable. If a primary key exists, incoming rows are merged with matching rows that already exist. If no primary key exists, incoming rows are appended to the DataTable.

So either define a primary key or clear the table first.

Dim table = CType(DataGridView.DataSource, DataTable)
table.Clear()
' fill  ...

To define primary key(s) manually read this. To let it create automatically if they are defined in the database you need to set the MissingSchemaAction to AddWithKey:

' ...
dataAdapter.MissingSchemaAction =  MissingSchemaAction.AddWithKey
' fill ...