将特定的列从一个数据表复制到另一个

Question

This doesn't seem like something that should be confusing or difficult, but I'm having a hard time finding the answer to this problem. I want to copy columns with their data, not rows, from one large DataTable to a smaller one.

I have a DataTable with many columns of data (around 20), and a string array of the columns (4 ) that I want in the copied DataTable. Is there a reasonable way to accomplish this task?

Answer 1

You can clone the table, remove the columns you don't need, then perform a merge. Thanks to Yuriy's helpful comment, this cuts the code down significantly.

Dim columnsToKeep As String() = {"ColumnName1", "ColumnName2"}
Dim destTable As DataTable = sourceTable.Clone()

For index As Integer = destTable.Columns.Count - 1 To 0 Step - 1
    Dim columnName As String = destTable.Columns(index).ColumnName
    If Not columnsToKeep.Contains(columnName) Then
        destTable.Columns.RemoveAt(index)
    End If
Next

destTable.Merge(sourceTable, False, MissingSchemaAction.Ignore)

The MissingSchemaAction.Ignore will perform the merge and ignore the extra columns found in the sourceTable .