Define your own dialog box and get user input : Dialog : GUI Windows Form C# Source Code

    

  using System;
  using System.Resources;
  using System.Drawing;
  using System.Collections;
  using System.Windows.Forms;
  using System.Resources;

  class Test
  {
    static void Main(string[] args)
    {
      SomeCustomForm myForm = new SomeCustomForm();
      myForm.Message = "Message";

      myForm.ShowDialog(new Form());

      if(myForm.DialogResult == DialogResult.OK)
      {
        Console.WriteLine(myForm.Message);
      }
    }
  }
    
    public class SomeCustomForm : System.Windows.Forms.Form
    {
        private System.ComponentModel.Container components;
    private System.Windows.Forms.Button btnCancel;
    private System.Windows.Forms.Button btnOK;
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.TextBox txtMessage;

        public SomeCustomForm()
        {
            InitializeComponent();
      this.StartPosition = FormStartPosition.CenterParent;      
        }

    private string strMessage;

    public string Message
    {
      get{ return strMessage;}
      set
      { 
        strMessage = value;
        txtMessage.Text = strMessage;
      }
    }


    protected override void Dispose( bool disposing )
    {
      if( disposing )
      {
        if (components != null) 
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }


    #region Windows Form Designer generated code
        private void InitializeComponent()
    {
      this.components = new System.ComponentModel.Container ();
      this.label1 = new System.Windows.Forms.Label ();
      this.btnOK = new System.Windows.Forms.Button ();
      this.btnCancel = new System.Windows.Forms.Button ();
      this.txtMessage = new System.Windows.Forms.TextBox ();
      label1.Location = new System.Drawing.Point (12, 8);
      label1.Text = "Type in your message.";
      label1.Size = new System.Drawing.Size (240, 48);
      label1.TabIndex = 1;

      btnOK.Location = new System.Drawing.Point (16, 104);
      btnOK.DialogResult = System.Windows.Forms.DialogResult.OK;
      btnOK.Size = new System.Drawing.Size (96, 24);
      btnOK.TabIndex = 2;
      btnOK.Text = "OK";
      btnOK.Click += new System.EventHandler (this.btnOK_Click);
      btnCancel.Location = new System.Drawing.Point (152, 104);
      btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel;
      btnCancel.Size = new System.Drawing.Size (96, 24);
      btnCancel.TabIndex = 3;
      btnCancel.Text = "Cancel";
      txtMessage.Location = new System.Drawing.Point (16, 72);
      txtMessage.TabIndex = 0;
      txtMessage.Size = new System.Drawing.Size (232, 20);
      this.Text = "Some Custom Dialog";
      this.MaximizeBox = false;
      this.AutoScaleBaseSize = new System.Drawing.Size (5, 13);
      this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
      this.ControlBox = false;
      this.MinimizeBox = false;
      this.ClientSize = new System.Drawing.Size (266, 151);
      this.Controls.Add (this.btnCancel);
      this.Controls.Add (this.btnOK);
      this.Controls.Add (this.label1);
      this.Controls.Add (this.txtMessage);
    }
    #endregion

    protected void btnOK_Click (object sender, System.EventArgs e)
    {
      // OK button clicked.
      // get new message.
      strMessage = txtMessage.Text;
    }
    }