DataColumn and precision

Does anyone have any idea how to set the precision of a column? The DataColumn object gives most properties, but precision. However using the server explorer you can get the precision details of a column in a table, as a property, so its got to be foalting around somewhere.

Cheers

VB Code:

Dim myDataColumn As DataColumn
Dim myDataRow As DataRow
Dim SampleTable As DataTable
Dim SampleDataSet as DataSet
 
myDataColumn = New DataColumn()
myDataColumn.ColumnName = "SampleTable"
SampleTable.Columns.Add(myDataColumn)
myDataColumn.ReadOnly = True
myDataColumn.DataType = System.Type.GetType("System.Double")
 
Me.DataGrid1.SetDataBinding(SampleDataSet, "SampleTable")