Dictionary<TKey, TValue> Constructor (Int32, IEqualityComparer<TKey>)

Parameters

• capacity
  Type: System.Int32
  The initial number of elements that the Dictionary<TKey, TValue> can contain.

• comparer
  Type: System.Collections.Generic.IEqualityComparer<TKey>
  The IEqualityComparer<T> implementation to use when comparing keys, or nulla null reference (Nothing in Visual Basic) to use the default EqualityComparer<T> for the type of the key.

Imports System.Collections.Generic

Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Create a new Dictionary of strings, with string keys, an
      ' initial capacity of 5, and a case-insensitive equality
      ' comparer.
      Dim openWith As New Dictionary(Of String, String)(5, _
          StringComparer.CurrentCultureIgnoreCase)

      ' Add 4 elements to the dictionary. 
      openWith.Add("txt", "notepad.exe")
      openWith.Add("bmp", "paint.exe")
      openWith.Add("DIB", "paint.exe")
      openWith.Add("rtf", "wordpad.exe")

      ' Try to add a fifth element with a key that is the same 
      ' except for case; this would be allowed with the default
      ' comparer.
      Try
         openWith.Add("BMP", "paint.exe")
      Catch ex As ArgumentException
         outputBlock.Text &= vbLf & "BMP is already in the dictionary." & vbCrLf
      End Try

      ' List the contents of the dictionary.
      outputBlock.Text &= vbCrLf
      For Each kvp As KeyValuePair(Of String, String) In openWith
         outputBlock.Text &= String.Format("Key = {0}, Value = {1}", _
             kvp.Key, kvp.Value) & vbCrLf
      Next kvp

   End Sub

End Class

' This code example produces the following output:
'
'BMP is already in the dictionary.
'
'Key = txt, Value = notepad.exe
'Key = bmp, Value = paint.exe
'Key = DIB, Value = paint.exe
'Key = rtf, Value = wordpad.exe

using System;
using System.Collections.Generic;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create a new dictionary of strings, with string keys, an
      // initial capacity of 5, and a case-insensitive equality 
      // comparer.
      Dictionary<string, string> openWith =
                    new Dictionary<string, string>(5,
                        StringComparer.CurrentCultureIgnoreCase);

      // Add 4 elements to the dictionary. 
      openWith.Add("txt", "notepad.exe");
      openWith.Add("bmp", "paint.exe");
      openWith.Add("DIB", "paint.exe");
      openWith.Add("rtf", "wordpad.exe");

      // Try to add a fifth element with a key that is the same 
      // except for case; this would be allowed with the default
      // comparer.
      try
      {
         openWith.Add("BMP", "paint.exe");
      }
      catch (ArgumentException)
      {
         outputBlock.Text += "\nBMP is already in the dictionary." + "\n";
      }

      // List the contents of the dictionary.
      outputBlock.Text += "\n";
      foreach (KeyValuePair<string, string> kvp in openWith)
      {
         outputBlock.Text += String.Format("Key = {0}, Value = {1}", kvp.Key,
             kvp.Value) + "\n";
      }
   }
}

/* This code example produces the following output:

BMP is already in the dictionary.

Key = txt, Value = notepad.exe
Key = bmp, Value = paint.exe
Key = DIB, Value = paint.exe
Key = rtf, Value = wordpad.exe
 */