// Fig. 5.16: IndexerTest.cs
// Indexers provide access to an object's members via a
// subscript operator.
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
namespace IndexerTest
{
// Box class definition represents a box with length,
// width and height dimensions
public class Box
{
private string[] names = { "length", "width", "height" };
private double[] dimensions = new double[ 3 ];
// constructor
public Box( double length, double width, double height )
{
dimensions[ 0 ] = length;
dimensions[ 1 ] = width;
dimensions[ 2 ] = height;
}
// access dimensions by index number
public double this[ int index ]
{
get
{
return ( index < 0 || index > dimensions.Length ) ?
-1 : dimensions[ index ];
}
set
{
if ( index >= 0 && index < dimensions.Length )
dimensions[ index ] = value;
}
} // end numeric indexer
// access dimensions by their names
public double this[ string name ]
{
get
{
// locate element to get
int i = 0;
while ( i < names.Length &&
name.ToLower() != names[ i ] )
i++;
return ( i == names.Length ) ? -1.0 : dimensions[ i ];
}
set
{
// locate element to set
int i = 0;
while ( i < names.Length &&
name.ToLower() != names[ i ] )
i++;
if ( i != names.Length )
dimensions[ i ] = value;
}
} // end indexer
} // end class Box
// Class IndexerTest
public class IndexerTest : System.Windows.Forms.Form
{
private System.Windows.Forms.Label indexLabel;
private System.Windows.Forms.Label nameLabel;
private System.Windows.Forms.TextBox indexTextBox;
private System.Windows.Forms.TextBox valueTextBox;
private System.Windows.Forms.Button nameSetButton;
private System.Windows.Forms.Button nameGetButton;
private System.Windows.Forms.Button intSetButton;
private System.Windows.Forms.Button intGetButton;
private System.Windows.Forms.TextBox resultTextBox;
// required designer variable
private System.ComponentModel.Container components = null;
private Box box;
// constructor
public IndexerTest()
{
// required for Windows Form Designer support
InitializeComponent();
// create block
box = new Box( 0.0, 0.0, 0.0 );
}
///
/// Clean up any resources being used.
///
protected override void Dispose( bool disposing )
{
if ( disposing )
{
if ( components != null )
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows Form Designer generated code
///
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///
private void InitializeComponent()
{
this.valueTextBox = new System.Windows.Forms.TextBox();
this.indexTextBox = new System.Windows.Forms.TextBox();
this.indexLabel = new System.Windows.Forms.Label();
this.nameLabel = new System.Windows.Forms.Label();
this.nameSetButton = new System.Windows.Forms.Button();
this.intGetButton = new System.Windows.Forms.Button();
this.intSetButton = new System.Windows.Forms.Button();
this.nameGetButton = new System.Windows.Forms.Button();
this.resultTextBox = new System.Windows.Forms.TextBox();
this.SuspendLayout();
//
// valueTextBox
//
this.valueTextBox.Location = new System.Drawing.Point(96, 41);
this.valueTextBox.Name = "valueTextBox";
this.valueTextBox.Size = new System.Drawing.Size(104, 20);
this.valueTextBox.TabIndex = 1;
this.valueTextBox.Text = "";
//
// indexTextBox
//
this.indexTextBox.Location = new System.Drawing.Point(96, 9);
this.indexTextBox.Name = "indexTextBox";
this.indexTextBox.Size = new System.Drawing.Size(104, 20);
this.indexTextBox.TabIndex = 0;
this.indexTextBox.Text = "";
//
// indexLabel
//
this.indexLabel.Location = new System.Drawing.Point(8, 11);
this.indexLabel.Name = "indexLabel";
this.indexLabel.Size = new System.Drawing.Size(88, 16);
this.indexLabel.TabIndex = 8;
this.indexLabel.Text = "Index to set/get";
//
// nameLabel
//
this.nameLabel.Location = new System.Drawing.Point(8, 43);
this.nameLabel.Name = "nameLabel";
this.nameLabel.Size = new System.Drawing.Size(88, 16);
this.nameLabel.TabIndex = 9;
this.nameLabel.Text = "Value to set";
//
// nameSetButton
//
this.nameSetButton.Location = new System.Drawing.Point(368, 40);
this.nameSetButton.Name = "nameSetButton";
this.nameSetButton.Size = new System.Drawing.Size(136, 23);
this.nameSetButton.TabIndex = 7;
this.nameSetButton.Text = "Set Value by Name";
this.nameSetButton.Click += new System.EventHandler(this.nameSetButton_Click);
//
// intGetButton
//
this.intGetButton.Location = new System.Drawing.Point(224, 8);
this.intGetButton.Name = "intGetButton";
this.intGetButton.Size = new System.Drawing.Size(136, 23);
this.intGetButton.TabIndex = 4;
this.intGetButton.Text = "Get Value by Index";
this.intGetButton.Click += new System.EventHandler(this.intGetButton_Click);
//
// intSetButton
//
this.intSetButton.Location = new System.Drawing.Point(368, 8);
this.intSetButton.Name = "intSetButton";
this.intSetButton.Size = new System.Drawing.Size(136, 23);
this.intSetButton.TabIndex = 5;
this.intSetButton.Text = "Set Value by Index";
this.intSetButton.Click += new System.EventHandler(this.intSetButton_Click);
//
// nameGetButton
//
this.nameGetButton.Location = new System.Drawing.Point(224, 40);
this.nameGetButton.Name = "nameGetButton";
this.nameGetButton.Size = new System.Drawing.Size(136, 23);
this.nameGetButton.TabIndex = 6;
this.nameGetButton.Text = "Get Value by Name";
this.nameGetButton.Click += new System.EventHandler(this.nameGetButton_Click);
//
// resultTextBox
//
this.resultTextBox.Location = new System.Drawing.Point(8, 80);
this.resultTextBox.Name = "resultTextBox";
this.resultTextBox.Size = new System.Drawing.Size(496, 20);
this.resultTextBox.TabIndex = 10;
this.resultTextBox.Text = "";
//
// IndexerTest
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(512, 109);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
this.resultTextBox,
this.nameLabel,
this.indexLabel,
this.nameSetButton,
this.nameGetButton,
this.intSetButton,
this.intGetButton,
this.valueTextBox,
this.indexTextBox});
this.Name = "IndexerTest";
this.Text = "IndexerTest";
this.ResumeLayout(false);
}
#endregion
// main entry point for application
[STAThread]
static void Main()
{
Application.Run( new IndexerTest() );
}
// display value at specified index number
private void ShowValueAtIndex( string prefix, int index )
{
resultTextBox.Text =
prefix + "box[ " + index + " ] = " + box[ index ];
}
// display value with specified name
private void ShowValueAtIndex( string prefix, string name )
{
resultTextBox.Text =
prefix + "box[ " + name + " ] = " + box[ name ];
}
// clear indexTextBox and valueTextBox
private void ClearTextBoxes()
{
indexTextBox.Text = "";
valueTextBox.Text = "";
}
// get value at specified index
private void intGetButton_Click(
object sender, System.EventArgs e )
{
ShowValueAtIndex(
"get: ", Int32.Parse( indexTextBox.Text ) );
ClearTextBoxes();
}
// set value at specified index
private void intSetButton_Click(
object sender, System.EventArgs e )
{
int index = Int32.Parse( indexTextBox.Text );
box[ index ] = Double.Parse( valueTextBox.Text );
ShowValueAtIndex( "set: ", index );
ClearTextBoxes();
}
// get value with specified name
private void nameGetButton_Click(
object sender, System.EventArgs e )
{
ShowValueAtIndex( "get: ", indexTextBox.Text );
ClearTextBoxes();
}
// set value with specified name
private void nameSetButton_Click(
object sender, System.EventArgs e )
{
box[ indexTextBox.Text ] =
Double.Parse( valueTextBox.Text );
ShowValueAtIndex( "set: ", indexTextBox.Text );
ClearTextBoxes();
}
} // end class IndexerTest
}
/*
**************************************************************************
* (C) Copyright 2003 by Deitel & Associates, Inc. and Prentice Hall. *
* All Rights Reserved. *
* *
* DISCLAIMER: The authors and publisher of this book have used their *
* best efforts in preparing the book. These efforts include the *
* development, research, and testing of the theories and programs *
* to determine their effectiveness. The authors and publisher make *
* no warranty of any kind, expressed or implied, with regard to these *
* programs or to the documentation contained in these books. The authors *
* and publisher shall not be liable in any event for incidental or *
* consequential damages in connection with, or arising out of, the *
* furnishing, performance, or use of these programs. *
**************************************************************************
*/
