System.Data.DataColumn.DataType Property

Gets or sets the type of data stored in the column.


public Type DataType { set; get; }


Documentation for this section has not yet been entered.


Setting the DataColumn.DataType value is very important to guaranteeing the correct creation and updating of data in a data source.

The DataColumn.DataType property supports the following base .NET Framework data types:

as well as the following array type:

  • Byte[]

An exception is generated when changing this property after the column has begun storing data.

If DataColumn.AutoIncrement is set to true before setting the DataColumn.DataType property, and you try to set the type to anything except an integer type, an exception is generated.


A column of data type Byte[] requires special treatment in certain cases since, unlike the base .NET Framework data types, it is a reference data type. If a column of data type Byte[] is used as a DataTable.PrimaryKey, or as a DataView.Sort or DataView.RowFilter key for a System.Data.DataView, any change to the column value must involve assigning the Byte[] column value to a separately instantiated Byte[] object. This assignment is required to trigger the update of the internal indexes used by sorting, filtering, and primary key operations. This is illustrated by the following example:


byte[] columnValue = (byte[])myDataTable.Rows[0][0];
byte[] newValue = (byte[])columnValue.Clone();
newValue[1] = 2;
myDataTable.Rows[0][0] = newValue;

Although it is possible to define a column as data type other than the base .NET Framework data types and Byte[], such a column will be treated as a user-defined type, subject to the following usage restrictions. (For more information on user-defined types, see Creating and Using User-Defined Types.)


Namespace: System.Data
Assembly: System.Data (in System.Data.dll)
Assembly Versions: 1.0.5000.0,