GetChars(Int32,Int64,Char[],Int32,Int32) Method

In This Topic

Reads a stream of characters from the specified column offset into the buffer as an array starting at the given buffer offset.

Syntax

Visual Basic
C#

'Declaration
 
Public Overloads Overrides Function GetChars( _
   ByVal i As Integer, _
   ByVal fieldOffset As Long, _
   ByVal buffer() As Char, _
   ByVal bufferOffset As Integer, _
   ByVal length As Integer _
) As Long

public override long GetChars( 
   int i,
   long fieldOffset,
   char[] buffer,
   int bufferOffset,
   int length
)

Parameters

i: The zero-based column ordinal.
fieldOffset: The index within the field where the read operation is to begin.
buffer: The buffer into which to copy data.
bufferOffset: The index within the buffer where the write operation is to begin.
length: The maximum number of characters to read.

Return Value

The actual number of characters read.

Remarks

GetChars returns the number of available characters in the field. In most cases this is the exact length of the field. However, the number returned may be less than the true length of the field if GetChars has already been used to obtain characters from the field. This may be the case, for example, if the MySqlDataReader is reading a large data structure into a buffer.

If you pass a buffer that is a null value. GetChars returns the length of the field in characters.

Example

This sample shows how to read data from a field into array of chars.

csharp

static void GetThatChars(MySqlConnection myConnection)
{
  MySqlCommand cmd = new MySqlCommand("SELECT * FROM Test.Dept");
  cmd.Connection = myConnection;
  myConnection.Open();
  try
  {
    MySqlDataReader reader = cmd.ExecuteReader();
    reader.Read();
    char[] myChars = new char[50];
    long bytesRead = reader.GetChars(reader.GetOrdinal("DName"),0,myChars,0,50);
    Console.WriteLine(bytesRead+ " bytes read from the table.");
    Console.WriteLine(myChars);
    reader.Close();
  }
  finally
  {
    myConnection.Close();
  }
}

Visual Basic

Public Sub GetThatChars(ByVal myConnection As MySqlConnection)
  Dim cmd As MySqlCommand = New MySqlCommand("SELECT * FROM Test.Dept")
  cmd.Connection = myConnection
  myConnection.Open()
  Try
    Dim reader As MySqlDataReader = cmd.ExecuteReader()
    reader.Read()
    Dim myChars(50) As Char
    Dim bytesRead As Long = reader.GetChars(reader.GetOrdinal("DName"), 0, myChars, 0, 50)
    Console.WriteLine(bytesRead & " bytes read from the table.")
    Console.WriteLine(myChars)
    reader.Close()
  Finally
    myConnection.Close()
  End Try
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

MySqlDataReader Class
MySqlDataReader Members
Overload List

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