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How do you create a new DataTable column expression using a column name and a variable?

How do you create a new DataTable column expression using a columnName * variableName?

The following gives creates a new column, and an expression of MyColumn * (a fixed value)

' Create the new column.
Dim MyNewColumn As New DataColumn
MyNewColumn.ColumnName = "MyColumnName"
MyNewColumn.Expression = "AnotherColumnName * 7"

' Add column to DataTable
Me.MyDataSet.MyDataTable.Columns.Add(MyNewColumn)

In the above example, I am after the 7 being a variable, not a predetermined fixed value.

Nandakumar Sakthivel

Try this link

http://www.informit.com/guides/content.asp?g=dotnet&seqNum=322&rl=1

Thanks,
Nanda

ASKER CERTIFIED SOLUTION

arif_eqbal

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Nandakumar Sakthivel

Try this.,

Dim x As Integer = 9 // assign the value that you want to multiply with the column here

Dim ds As New DataSet
Dim dt As New DataTable
Dim dr As DataRow

Dim column1 As New DataColumn
column1.ColumnName = "Number"
column1.DataType = GetType(Integer)
dt.Columns.Add(column1)

Dim column2 As New DataColumn
column2.ColumnName = "MinValue"
column2.DataType = GetType(Integer)
dt.Columns.Add(column2)

Dim column3 As New DataColumn
column3.ColumnName = "TotalValue"
column3.DataType = GetType(Integer)
column3.Expression = String.Format("Number * {0}", x)
dt.Columns.Add(column3)

dr = dt.NewRow
dr.item(0) = 5
dr.item(1) = 10
dt.Rows.Add(dr)

dr = dt.NewRow
dr.item(0) = 20
dr.item(1) = 30
dt.Rows.Add(dr)

Thanks,
Nanda

IvanHowarth

ASKER

arif_eqbal answer was exactly what I needed.

Thanks both anyway.