A class that persists form settings automatically

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Introduction

A common need for Windows forms is to remember the last position, size and state of the form. One way to do this is to call a function when your form loads and closes. I decided to do it the Object Oriented way. If your form inherits this class, it will automatically load and save the the form settings; Left, Top, Height, Width, and State; to a .config file.

Using the code

To use this class in a C# project

• Add the "PersistentForm.cs" class to you project.
• Add "using KrugismSamples" to the list of references at the top of the form code.
• Change the:

  public class Form1 : System.Windows.Forms.Form

  to:

  public class Form1 : PersistentForm

That's it! When the form is loaded, the saved values are set to the form. When the form is closed, the settings are saved.

To use this class in a VB.NET project

• Add a new existing project to your VB solution, and browse to the "PersistentForm.csproj" file.
• Add a reference to the PersistentForm class in the Add Reference, Projects tab.
• Add "Imports KrugismSamples" to the top of the source.
• Change the:

Inherits System.Windows.Forms.Form

to:

Inherits PersistentForm

That's it! When the form is loaded, the saved values are set to the form. When the form is closed, the settings are saved.

Overview

This class is very straightforward. It simply inherits the Windows.Forms.Form class. It then overrides the OnCreateControl() and OnClosing() events. By overriding the base events, no additional code needs to be added to the form. (The LoadSettings() and SaveSettings() code is not shown here.)

public class PersistentForm : System.Windows.Forms.Form
{
    public PersistentForm()
    {
    }
    protected override void OnCreateControl()
    {
        LoadSettings();     // Load the saved settings from the file

        base.OnCreateControl ();
    }
   
    protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
    {
        SaveSettings();        // Save the settings to the file

        base.OnClosing(e);
    }
}

History

• 10-30-2003 - Edited for completeness
• 10-29-2003 - Initial Release