DataTableReader.GetString(Int32) Method

Definition

Namespace:

System.Data

Assembly:

System.Data.Common.dll

Source:

DataTableReader.cs

Gets the value of the specified column as a string.

public:
 override System::String ^ GetString(int ordinal);

public override string GetString (int ordinal);

override this.GetString : int -> string

Public Overrides Function GetString (ordinal As Integer) As String

Parameters

ordinal

Int32

The zero-based column ordinal.

Returns

String

The value of the specified column.

Exceptions

ArgumentOutOfRangeException

The index passed was outside the range of 0 to FieldCount - 1.

DeletedRowInaccessibleException

An attempt was made to retrieve data from a deleted row.

InvalidOperationException

An attempt was made to read or access a column in a closed DataTableReader.

InvalidCastException

The specified column does not contain a string.

Examples

The following example displays the contents of the column numbered 2 within the passed-in DataTableReader. If the value the column within a particular row is null, the code displays the text <NULL>. If the data within the column of the correct type, the example displays an error message for each row.

private static void PrintColumn(DataTableReader reader)
{
    // Loop through all the rows in the DataTableReader
    while (reader.Read())
    {
        if (reader.IsDBNull(2))
        {
            Console.Write("<NULL>");
        }
        else
        {
            try
            {
                Console.Write(reader.GetString(2));
            }
            catch (InvalidCastException)
            {
                Console.Write("Invalid data type.");
            }
        }
        Console.WriteLine();
    }
}

Private Sub PrintColumn(ByVal reader As DataTableReader)
   ' Loop through all the rows in the DataTableReader
   While reader.Read()
      If reader.IsDBNull(2) Then
         Console.Write("<NULL>")
      Else
         Try
            Console.Write(reader.GetString(2))
         Catch ex As InvalidCastException
            Console.Write("Invalid data type.")
         End Try
      End If
      Console.WriteLine()
   End While
End Sub

Remarks

Call IsDBNull to see if there are null values before calling this method.