Article
11/18/2011

String.Concat Method (Object, Object)

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Updated: October 2010

Concatenates the string representations of two specified objects.

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

Syntax

'Declaration
Public Shared Function Concat ( _
    arg0 As Object, _
    arg1 As Object _
) As String

public static string Concat(
    Object arg0,
    Object arg1
)

Parameters

arg0
Type: System.Object
The first object to concatenate.

arg1
Type: System.Object
The second object to concatenate.

Return Value

Type: System.String
The concatenated string representations of the values of arg0 and arg1.

Remarks

The method concatenates arg0 and arg1 by calling the parameterless ToString method of arg0 and arg1; it does not add any delimiters.

String.Empty is used in place of any null argument.

If either of the arguments is an array reference, the method concatenates a string representing that array, instead of its members (for example, "System.String[]").

Examples

The following code example demonstrates the Concat method.

 _

Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim i As Integer = -123
      Dim o As [Object] = i
      Dim objs() As [Object] = {-123, -456, -789}

      outputBlock.Text += String.Format("Concatenate 1, 2, and 3 objects:") & vbCrLf
      outputBlock.Text += String.Format("1) {0}", [String].Concat(o)) & vbCrLf
      outputBlock.Text += String.Format("2) {0}", [String].Concat(o, o)) & vbCrLf
      outputBlock.Text += String.Format("3) {0}", [String].Concat(o, o, o)) & vbCrLf

      outputBlock.Text &= vbCrLf & "Concatenate 4 objects and a variable length parameter list:" & vbCrLf
      outputBlock.Text += String.Format("4) {0}", [String].Concat(o, o, o, o, o)) & vbCrLf

      outputBlock.Text &= vbCrLf & "Concatenate a 3 element object array:" & vbCrLf
      outputBlock.Text += String.Format("5) {0}", [String].Concat(objs)) & vbCrLf
   End Sub 'Main
End Class 'stringConcat5
'
'This example produces the following output:
'Concatenate 1, 2, and 3 objects:
'1) -123
'2) -123-123
'3) -123-123-123
'
'Concatenate 4 objects and a variable length parameter list:
'4) -123-123-123-123-123
'
'Concatenate a 3 element object array:
'5) -123-456-789
'

using System;

class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      int i = -123;
      Object o = i;
      Object[] objs = new Object[] { -123, -456, -789 };

      outputBlock.Text += String.Format("Concatenate 1, 2, and 3 objects:") + "\n";
      outputBlock.Text += String.Format("1) {0}", String.Concat(o)) + "\n";
      outputBlock.Text += String.Format("2) {0}", String.Concat(o, o)) + "\n";
      outputBlock.Text += String.Format("3) {0}", String.Concat(o, o, o)) + "\n";

      outputBlock.Text += "\nConcatenate 4 objects and a variable length parameter list:" + "\n";
      outputBlock.Text += String.Format("4) {0}", String.Concat(o, o, o, o, o)) + "\n";

      outputBlock.Text += "\nConcatenate a 3 element object array:" + "\n";
      outputBlock.Text += String.Format("5) {0}", String.Concat(objs)) + "\n";
   }
}
/*
This example produces the following output:
Concatenate 1, 2, and 3 objects:
1) -123
2) -123-123
3) -123-123-123

Concatenate 4 objects and a variable length parameter list:
4) -123-123-123-123-123

Concatenate a 3 element object array:
5) -123-456-789
*/

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Change History

Date	History	Reason
October 2010	Revised the Remarks section.	Customer feedback.

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