Button的DialogResult.OK有关问题

Button的DialogResult.OK问题？

C# code

如果将button的DialogResult设为OK，验证失败后，它会直接关闭窗口，这时，我们要求在验证失败后重新输入，而不是关闭窗口，请问怎么做？主窗口：  #region            //if (RValue == "")            //{            //    MessageBox.Show(this, "请选择需要修改的数据！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);            //    return;            //}            Login.FLAGID = "10";            NewClientAdd editor = new NewClientAdd();            editor.ShowDialog();            if (editor.DialogResult == DialogResult.OK)            {                DataGridViewBind2();            }            #endregion子窗口：      Button的DialogResult.OK

C# code

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows.Forms;namespace TestDialog{    class Program    {        static void Main(string[] args)        {            Application.Run(new MainForm());        }    }    class MainForm : Form    {        Button cmdTest;        public MainForm()        {            this.SetBounds(0, 0, 300, 400);            this.StartPosition = FormStartPosition.CenterScreen;            this.Text = "Main Form";            cmdTest = new Button();            cmdTest.SetBounds(100, 180, 100, 40);            cmdTest.Text = "Test";            cmdTest.Click += (o, e) =>            {                TestForm frm = new TestForm();                frm.ShowDialog();                MessageBox.Show("DialogResult: " + frm.DialogResult);            };            this.Controls.Add(cmdTest);        }    }    class TestForm : Form    {        Button cmdTest;        TextBox txtTest;        public TestForm()        {            this.SetBounds(0, 0, 200, 200);            this.StartPosition = FormStartPosition.CenterParent;            this.Text = "Test Form";            txtTest = new TextBox();            txtTest.SetBounds(50, 50, 100, 30);            cmdTest = new Button();            cmdTest.SetBounds(70, 100, 60, 40);            cmdTest.Text = "Test";            cmdTest.Click += (o, e) =>            {                if (txtTest.Text == "123") this.DialogResult = System.Windows.Forms.DialogResult.OK;            };            this.Controls.Add(cmdTest);            this.Controls.Add(txtTest);        }    }}