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ListBox::Sort Method

Sorts the items in the ListBox.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

protected:
virtual void Sort()

Sort forces the collection to add each item back to itself if the Sorted property is true. Each item is then inserted into the correct position.

Notes to Inheritors

You can override this method in your derived class to provide your own sorting routine. Access the results of the overridden Sort method by setting the Sorted property to true. When adding items to a ListBox, it is more efficient to sort the items first and then add new items.

The following code example demonstrates using the Sort method. The example demonstrates inheriting from the ListBox class and overriding the Sort method in the derived class to perform a user-defined sort. To run this example paste the following code in an empty form.

// The following code example demonstrates using the ListBox.Sort method 
// by inheriting from the ListBox class and overriding the Sort method. 
using namespace System::Drawing;
using namespace System::Windows::Forms;

// This class inherits from ListBox and implements a different  
// sorting method. Sort will be called by setting the class's Sorted 
// property to True. 
public ref class SortByLengthListBox: public ListBox
{
public:
   SortByLengthListBox()
      : ListBox()
   {}

protected:

   // Overrides the parent class Sort to perform a simple 
   // bubble sort on the length of the string contained in each item. 
   virtual void Sort() override
   {
      if ( Items->Count > 1 )
      {
         bool swapped;
         do
         {
            int counter = Items->Count - 1;
            swapped = false;
            while ( counter > 0 )
            {

               // Compare the items' length.  
               if ( Items[ counter ]->ToString()->Length < Items[ counter - 1 ]->ToString()->Length )
               {

                  // Swap the items.
                  Object^ temp = Items[ counter ];
                  Items[ counter ] = Items[ counter - 1 ];
                  Items[ counter - 1 ] = temp;
                  swapped = true;
               }

               // Decrement the counter.
               counter -= 1;
            }
         }
         while ( (swapped == true) );
      }
   }
};

public ref class Form1: public System::Windows::Forms::Form
{
internal:
   System::Windows::Forms::Button^ Button1;
   SortByLengthListBox^ sortingBox;

public:
   Form1()
      : Form()
   {
      this->Button1 = gcnew System::Windows::Forms::Button;
      this->sortingBox = gcnew SortByLengthListBox;
      this->SuspendLayout();
      this->Button1->Location = System::Drawing::Point( 64, 16 );
      this->Button1->Name = "Button1";
      this->Button1->Size = System::Drawing::Size( 176, 23 );
      this->Button1->TabIndex = 0;
      this->Button1->Text = "Click me for list sorted by length";
      this->Button1->Click += gcnew System::EventHandler( this, &Form1::Button1_Click );
      array<Object^>^temp0 = {"System","System.Windows.Forms","System.Xml","System.Net","System.Drawing","System.IO"};
      this->sortingBox->Items->AddRange( temp0 );
      this->sortingBox->Location = System::Drawing::Point( 72, 48 );
      this->sortingBox->Size = System::Drawing::Size( 120, 95 );
      this->sortingBox->TabIndex = 1;
      this->ClientSize = System::Drawing::Size( 292, 266 );
      this->Controls->Add( this->sortingBox );
      this->Controls->Add( this->Button1 );
      this->Name = "Form1";
      this->Text = "Sort Example";
      this->ResumeLayout( false );
   }

private:
   void Button1_Click( System::Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Set the Sorted property to True to raise the overridden Sort 
      // method.
      sortingBox->Sorted = true;
   }

};

int main()
{
   Application::Run( gcnew Form1 );
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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