Add Method (String)
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DataColumnCollection.Add Method (String)

 

Creates and adds a DataColumn object that has the specified name to the DataColumnCollection.

Namespace:   System.Data
Assembly:  System.Data (in System.Data.dll)

public DataColumn Add(
	string columnName
)

Parameters

columnName
Type: System.String

The name of the column.

Return Value

Type: System.Data.DataColumn

The newly created DataColumn.

Exception Condition
DuplicateNameException

The collection already has a column with the specified name. (The comparison is not case-sensitive.)

By default, the DataType for the new column is string.

If null or an empty string ("") is passed in for the name, a default name ("Column1", "Column2", and so on) is given to the column.

Use the Contains method to determine whether a column with the proposed name already exists in the collection.

If the collection is successfully changed by adding or removing columns, the CollectionChanged event occurs.

The following example creates and adds a new DataColumn to a DataColumnCollection of a DataTable.

Private Sub AddColumn()
    ' Get the DataColumnCollection from a table in a DataSet.
    Dim columns As DataColumnCollection = _
        DataSet1.Tables("Prices").Columns
    Dim column As DataColumn = columns.Add("Total")

    With column
       .DataType = System.Type.GetType("System.Decimal")
       .ReadOnly = True
       .Expression = "UnitPrice * Quantity"
       .Unique = False
    End With
End Sub

.NET Framework
Available since 1.1
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