C# MessageBox.show 是如何实现等待

直接把我写的代码给你，很好用的，跟messagebox的调用方法差不多，记得把命名空间改成你自己的：
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;

#region 直接调用该类的静态ShowInputBox方法就可以实现Microsoft.VisualBasic.Interaction.InputBox，其中Position参数是输入框位置，Title参数是输入框的标题，Prompt参数是提示标签，DefaultResponse可以显示自定义的默认信息。
/*
//具体调用如下:
private void button_Click(object sender, System.EventArgs e)
{
string inMsg = InputSystem.InputBox.ShowInputBox("输入框", "输入信息", string.Empty);
//对用户的输入信息进行检查
if (inMsg.Trim() != string.Empty) MessageBox.Show(inMsg);
else MessageBox.Show("输入为空");
}
*/
#endregion

namespace UVCE
{
///

/// InputBox 的摘要说明。
///

public class InputBox : System.Windows.Forms.Form
{
private System.Windows.Forms.Label label_Info;
private TextBox textBox_Data;
private Button button_Enter;
private Button button_Esc;
private System.ComponentModel.Container components = null;

private InputBox()
{
InitializeComponent();
this.TopMost = true;
//this.StartPosition = FormStartPosition.CenterScreen;
//inputbox.Location.X = 0; inputbox.Location.Y = 0;
//inputbox.StartPosition = FormStartPosition.CenterScreen;
//inputbox.Left = 0;
//inputbox.Top = 0;
}

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

private void InitializeComponent()
{
this.label_Info = new System.Windows.Forms.Label();
this.textBox_Data = new System.Windows.Forms.TextBox();
this.button_Enter = new System.Windows.Forms.Button();
this.button_Esc = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// label_Info
//
this.label_Info.BackColor = System.Drawing.SystemColors.ButtonFace;
this.label_Info.FlatStyle = System.Windows.Forms.FlatStyle.System;
this.label_Info.Font = new System.Drawing.Font("SimSun", 9F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
this.label_Info.ForeColor = System.Drawing.Color.Gray;
this.label_Info.Location = new System.Drawing.Point(10, 35);
this.label_Info.Name = "label_Info";
this.label_Info.Size = new System.Drawing.Size(147, 46);
this.label_Info.TabIndex = 1;
this.label_Info.Text = "[Enter]确认|[Esc]取消";
this.label_Info.TextAlign = System.Drawing.ContentAlignment.MiddleLeft;
//
// textBox_Data
//
this.textBox_Data.Location = new System.Drawing.Point(7, 7);
this.textBox_Data.Name = "textBox_Data";
this.textBox_Data.Size = new System.Drawing.Size(191, 20);
this.textBox_Data.TabIndex = 2;
this.textBox_Data.KeyDown += new System.Windows.Forms.KeyEventHandler(this.textBox_Data_KeyDown);
//
// button_Enter
//
this.button_Enter.Location = new System.Drawing.Point(162, 40);
this.button_Enter.Name = "button_Enter";
this.button_Enter.Size = new System.Drawing.Size(42, 18);
this.button_Enter.TabIndex = 3;
this.button_Enter.Text = "确 认";
this.button_Enter.UseVisualStyleBackColor = true;
this.button_Enter.Click += new System.EventHandler(this.button_Enter_Click);
//
// button_Esc
//
this.button_Esc.Location = new System.Drawing.Point(162, 64);
this.button_Esc.Name = "button_Esc";
this.button_Esc.Size = new System.Drawing.Size(42, 19);
this.button_Esc.TabIndex = 4;
this.button_Esc.Text = "取 消";
this.button_Esc.UseVisualStyleBackColor = true;
this.button_Esc.Click += new System.EventHandler(this.button_Esc_Click);
//
// InputBox
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(250, 96);
this.Controls.Add(this.button_Esc);
this.Controls.Add(this.button_Enter);
this.Controls.Add(this.textBox_Data);
this.Controls.Add(this.label_Info);
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
this.MaximizeBox = false;
this.MinimizeBox = false;
this.Name = "InputBox";
this.Text = "InputBox";
this.Load += new System.EventHandler(this.InputBox_Load);
this.ResumeLayout(false);
this.PerformLayout();

}

//对键盘进行响应
private void textBox_Data_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter) { button_Enter_Click(sender, e); }
else if (e.KeyCode == Keys.Escape) { button_Esc_Click(sender, e); }
}
private void button_Enter_Click(object sender, EventArgs e)
{
this.Close();
}
private void button_Esc_Click(object sender, EventArgs e)
{
textBox_Data.Text = string.Empty; this.Close();
}

//显示InputBox
public static string ShowInputBox(int Left, int Top, string Title, string Prompt, string DefaultResponse)
{
InputBox inputbox = new InputBox();
if (Title.Trim() != string.Empty) inputbox.Text = Title;
if (Prompt.Trim() != string.Empty) inputbox.label_Info.Text = Prompt;
if (DefaultResponse.Trim() != string.Empty) inputbox.textBox_Data.Text = DefaultResponse;
inputbox.ShowDialog();
inputbox.Left = Left; inputbox.Top = Top;
return inputbox.textBox_Data.Text;
}
public static string ShowInputBox(FormStartPosition Position, string Title, string Prompt, string DefaultResponse)
{
InputBox inputbox = new InputBox();
inputbox.StartPosition = Position;
if (Title.Trim() != string.Empty) inputbox.Text = Title;
if (Prompt.Trim() != string.Empty) inputbox.label_Info.Text = Prompt;
if (DefaultResponse.Trim() != string.Empty) inputbox.textBox_Data.Text = DefaultResponse;
inputbox.ShowDialog();
return inputbox.textBox_Data.Text;
}
public static string ShowInputBox()
{
return ShowInputBox(FormStartPosition.CenterScreen, string.Empty, string.Empty, string.Empty);
}
public static string ShowInputBox(string Title)
{
return ShowInputBox(FormStartPosition.CenterScreen, Title, string.Empty, string.Empty);
}
public static string ShowInputBox(string Title, string Prompt)
{
return ShowInputBox(FormStartPosition.CenterScreen, Title, Prompt, string.Empty);
}
public static string ShowInputBox(string Title, string Prompt, string DefaultResponse)
{
return ShowInputBox(FormStartPosition.CenterScreen, Title, Prompt, DefaultResponse);
}

private void InputBox_Load(object sender, EventArgs e)
{

}
}
}

if(DialogResult.Yes == MessageBox.Show("XXXX?", "警告", MessageBoxButtons.YesNo))
{
XXXXX
}

如果是窗口间传递就声明一个全局变量，然后把控件改为public

试验步骤:放好铁架台，铁棒一端沾少许护手霜，另一端不沾并用铁架台固定其中央，用火柴点燃酒精灯，放在铁棒无护手霜一端下面，
试验现象：N分钟后护手霜溶化，
试验结论：铁棒有导热作用。

inputbox.ShowDialog();
return inputbox.textBox_Data.Text;
这个一显示窗口就返回Text了, 有用吗?

？？？？？？？？？怎么会一显示就返回TEXT。。

ShowDialog为模式显示。和MessageBox一样，需要窗体关闭后才会执行后面的代码。也就是说
当inputbox窗体关闭后，return inputbox.textBox_Data.Text;才会执行

c#中一般默认的方法修饰符就是private 如果是外部方法需要调用的话，就要将修饰符写成public，像void show()就是
private void show()