canceledit.cpp

#using <System.Data.dll>
#using <System.Xml.dll>
#using <System.Windows.Forms.dll>
#using <System.dll>
#using <System.Drawing.dll>

usingnamespaceSystem;
usingnamespaceSystem::Drawing;
usingnamespaceSystem::Collections;
usingnamespaceSystem::ComponentModel;
usingnamespaceSystem::Windows::Forms;
usingnamespaceSystem::Data;

namespaceCancelEdit
{
/// <summary>
/// Summary description for Form1.
/// </summary>
 public ref classForm1: publicSystem::Windows::Forms::Form
 {
private:
 System::Windows::Forms::TextBox^ textBox1;
 DataView^ myDataView;

/// <summary>
/// Required designer variable.
/// </summary>
 System::ComponentModel::Container^ components;

public:
Form1()
 {
 components = nullptr;

//
// Required for Windows Form Designer support
//
InitializeComponent();

//
// TODO: Add any constructor code after InitializeComponent call
//
 }

protected:

/// <summary>
/// Clean up any resources being used.
/// </summary>
~Form1()
 {
if ( components != nullptr )
 {
delete components;
 }
 }

private:

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
voidInitializeComponent()
 {
this->textBox1 = gcnew System::Windows::Forms::TextBox;
this->SuspendLayout();

//
// textBox1
//
this->textBox1->Location = System::Drawing::Point( 24, 16 );
this->textBox1->Name = "textBox1";
this->textBox1->Size = System::Drawing::Size( 216, 20 );
this->textBox1->TabIndex = 0;
this->textBox1->Text = "textBox1";

//
// Form1
//
this->ClientSize = System::Drawing::Size( 292, 266 );
 array<System::Windows::Forms::Control^>^formControls = {this->textBox1};
this->Controls->AddRange( formControls );
this->Name = "Form1";
this->Text = "Form1";
this->Load += gcnew System::EventHandler( this, &Form1::Form1_Load );
this->ResumeLayout( false );
 }

voidForm1_Load( Object^ /*sender*/, System::EventArgs^ /*e*/ )
 {
SetBinding();
CancelEdit();
EndEdit();
 }

//<snippet1>
private:
voidCancelEdit()
 {
// Gets the CurrencyManager which is returned when the
// data source is a DataView.
 BindingManagerBase^ myMgr = dynamic_cast<CurrencyManager^>(BindingContext[ myDataView ]);

// Gets the current row and changes a value. Then cancels the
// edit and thereby discards the changes.
 DataRowView^ tempRowView = dynamic_cast<DataRowView^>(myMgr->Current);
Console::WriteLine( "Original: {0}", tempRowView[ "myCol" ] );
 tempRowView[ "myCol" ] = "These changes will be discarded";
Console::WriteLine( "Edit: {0}", tempRowView[ "myCol" ] );
 myMgr->CancelCurrentEdit();
Console::WriteLine( "After CanceCurrentlEdit: {0}", tempRowView[ "myCol" ] );
 }

voidEndEdit()
 {
// Gets the CurrencyManager which is returned when the
// data source is a DataView.
 BindingManagerBase^ myMgr = dynamic_cast<CurrencyManager^>(BindingContext[ myDataView ]);

// Gets the current row and changes a value. Then ends the
// edit and thereby keeps the changes.
 DataRowView^ tempRowView = dynamic_cast<DataRowView^>(myMgr->Current);
Console::WriteLine( "Original: {0}", tempRowView[ "myCol" ] );
 tempRowView[ "myCol" ] = "These changes will be kept";
Console::WriteLine( "Edit: {0}", tempRowView[ "myCol" ] );
 myMgr->EndCurrentEdit();
Console::WriteLine( "After EndCurrentEdit: {0}", tempRowView[ "myCol" ] );
 }
// </snippet1>

voidSetBinding()
 {
// Creates a DataView to be used as a data source. Sets the
// myDataView variable, defined in the form, to the DataView.
// Then binds the TextBox control to the DataView.
 DataTable^ myTable = gcnew DataTable( "myTable" );
 DataColumn^ myCol = gcnew DataColumn( "myCol" );
 myTable->Columns->Add( myCol );
 DataRow^ tempRow;
 tempRow = myTable->NewRow();
 tempRow[ "myCol" ] = "Original Data";
 myTable->Rows->Add( tempRow );
 myDataView = myTable->DefaultView;
 textBox1->DataBindings->Add( gcnew Binding( "Text",myDataView,"myCol" ) );
 }
 };
}


/// <summary>
/// The main entry point for the application.
/// </summary>

[STAThread]
intmain()
{
Application::Run( gcnew CancelEdit::Form1 );
}