Define Apply Button action method in dialog class : Dialog : GUI Windows Forms C# Examples

    
using  System;
using  System.Drawing;
using  System.Collections;
using  System.ComponentModel;
using  System.Windows.Forms;
using  System.Data;

public  class  DialogApplyMethodInDialogClass  :  System.Windows.Forms.Form
{
    private  System.Windows.Forms.Button  btnCreate;
    private  System.Windows.Forms.Label  lblReturn;

    public  DialogApplyMethodInDialogClass()
    {
        InitializeComponent();
    }
    private  void  InitializeComponent()
    {
        this.btnCreate  =  new  System.Windows.Forms.Button();
        this.lblReturn  =  new  System.Windows.Forms.Label();
        this.SuspendLayout();
        this.btnCreate.Location  =  new  System.Drawing.Point(80,  144);
        this.btnCreate.Name  =  "btnCreate";
        this.btnCreate.Size  =  new  System.Drawing.Size(136,  23);
        this.btnCreate.TabIndex  =  0;
        this.btnCreate.Text  =  "Create  Dialog  Box";
        this.btnCreate.Click  +=  new  System.EventHandler(this.btnCreate_Click);
        this.lblReturn.Location  =  new  System.Drawing.Point(88,  64);
        this.lblReturn.Name  =  "lblReturn";
        this.lblReturn.Size  =  new  System.Drawing.Size(152,  23);
        this.lblReturn.TabIndex  =  1;
        this.AutoScaleBaseSize  =  new  System.Drawing.Size(5,  13);
        this.ClientSize  =  new  System.Drawing.Size(292,  273);
        this.Controls.AddRange(new  System.Windows.Forms.Control[]  {
                                                                                          this.lblReturn,
                                                                                          this.btnCreate});
        this.ResumeLayout(false);
    }
    [STAThread]
    static  void  Main()  
    {
        Application.Run(new  DialogApplyMethodInDialogClass());
    }

    private  void  btnCreate_Click(object  sender,  System.EventArgs  e)
    {
        DialogDemo  dlg  =  new  DialogDemo(this);
        dlg.EnableApplyButton  =  false;

        dlg.ShowDialog();
        
        if  (dlg.DialogResult  ==  DialogResult.OK)
            {lblReturn.Text  =  dlg.TextOut;}
        else
            {lblReturn.Text  =  dlg.DialogResult.ToString();}
    }
    
    public  void  UpdateLabel(string  str)
    {
        lblReturn.Text  =  str;
    }

}
public  class  DialogDemo  :  Form
{
    private  Button  btnApply  =  new  Button();
    private  TextBox  txt  =  new  TextBox();
    private  DialogApplyMethodInDialogClass  f;
    
    public  DialogDemo(DialogApplyMethodInDialogClass  f)
    {
        this.f  =  f;
        FormBorderStyle  =  FormBorderStyle.FixedDialog;
        BackColor  =  System.Drawing.Color.Aquamarine;
        ControlBox  =  false;
        MaximizeBox  =  false;
        MinimizeBox  =  false;
        ShowInTaskbar  =  false;
        Size  =  new  Size(400,200);
        StartPosition  =  FormStartPosition.CenterScreen;

        Button  btnOK  =  new  Button();
        btnOK.Text  =  "OK";
        btnOK.DialogResult  =  DialogResult.OK;
        btnOK.Location  =  new  Point(50,50);
        btnOK.TabIndex  =  0;
        Controls.Add(btnOK);
        
        btnApply.Text  =  "Apply";
        btnApply.Location  =  new  Point(150,50);
        btnApply.TabIndex  =  1;
        btnApply.Enabled  =  false;
        btnApply.Click  +=  new  EventHandler(ApplyOnClick);
        Controls.Add(btnApply);
        
        Button  btnCancel  =  new  Button();
        btnCancel.Text  =  "Cancel";
        btnCancel.DialogResult  =  DialogResult.Cancel;
        btnCancel.Location  =  new  Point(250,50);
        btnCancel.TabIndex  =  2;
        Controls.Add(btnCancel);

        
        txt.Size  =  new  Size(100,15);
        txt.Location  =  new  Point(150,15);
        txt.TextChanged  +=  new  EventHandler(TextBoxChanged);
        Controls.Add(txt);
    }

    private  void  ApplyOnClick(object  sender,  EventArgs  e)
    {
        f.UpdateLabel(txt.Text);
        EnableApplyButton  =  false;
    }
    
    private  void  TextBoxChanged(object  sender,  EventArgs  e)
    {
        TextBox  txt  =  (TextBox)sender;
        DialogDemo  dlg  =  (DialogDemo)txt.Parent;
        dlg.EnableApplyButton  =  true;    
    }

    public  bool  EnableApplyButton
    {
        get  {return  btnApply.Enabled;  }
        set  {btnApply.Enabled  =  value;  }
    }
    
    public  string  TextOut
    {
        get
            {return  txt.Text;  }
    }
}