Question

I’m helping someone fix a VB application but struggling with a little bit of syntax.

I have the following:

Dim _dt = Datalayer.ConvertSqlDataSourceToDataTable(SqlDataSourceCart)
If _dt.Rows.Count > 0 Then
    'For Each here...
End If

What I need to do is loop through every row using a For or For Each loop and get the ProductID field. I think it should be along the lines of:

Dim someString As String   
For Each _row As DataRow In _dt.DataSet.Tables(0).Rows
    someString += _row(ProductID) & ", "
Next

Answer 1

Assuming _dt is alrady of type DataTable:

Dim someStringBuilder As New System.Text.StringBuilder()
For Each _row As DataRow In _dt.Rows
    someStringBuilder.Append(_row.Field(Of String)("ProductID")).Append(",")
Next
If someStringBuilder.Length<>0 Then someStringBuilder.Length -= 1
Dim someString = someStringBuilder.ToString()

or, if you can use LINQ-To-DataSet:

Dim IDs = _dt.AsEnumerable.Select(Function(r) r.Field(Of String)("ProductID"))
someString  = String.Join(",", IDs)