控件属性和InitializeComponent()关系：

 namespace Test22

 {

     partial class Form1

     {

         /// <summary>

         /// 必需的设计器变量。

         /// </summary>

         private System.ComponentModel.IContainer components = null;

         /// <summary>

         /// 清理所有正在使用的资源。

         /// </summary>

         /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>

         protected override void Dispose(bool disposing)

         {

             if (disposing && (components != null))

             {

                 components.Dispose();

             }

             base.Dispose(disposing);

         }

         #region Windows 窗体设计器生成的代码

         /// <summary>

         /// 设计器支持所需的方法 - 不要

         /// 使用代码编辑器修改此方法的内容。

         /// </summary>

         private void InitializeComponent()

         {

             this.numericUpDown1 = new System.Windows.Forms.NumericUpDown();

             ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).BeginInit();

             this.SuspendLayout();

             //

             // numericUpDown1

             //

             this.numericUpDown1.DecimalPlaces = ;//属性里对应！！！！！

             this.numericUpDown1.Location = new System.Drawing.Point(, );

             this.numericUpDown1.Name = "numericUpDown1";

             this.numericUpDown1.Size = new System.Drawing.Size(, );

             this.numericUpDown1.TabIndex = ;

             //

             // Form1

             //

             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);

             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;

             this.ClientSize = new System.Drawing.Size(, );

             this.Controls.Add(this.numericUpDown1);

             this.Name = "Form1";

             this.Text = "Form1";

             this.Load += new System.EventHandler(this.Form1_Load);

             ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).EndInit();

             this.ResumeLayout(false);

         }

         #endregion

         private System.Windows.Forms.NumericUpDown numericUpDown1;

     }

 }

控件中小数点位数和InitializeComponent()里面的代码相呼应，而下面的代码又设置了2，所以覆盖掉了，代码和运行结果如下：

 using System;

 using System.Data;

 using System.Drawing;

 using System.Text;

 using System.Windows.Forms;

 namespace Test22

 {

     public partial class Form1 : Form

     {

         public Form1()

         {

             InitializeComponent();

         }

         private void Form1_Load(object sender, EventArgs e)

         {

             numericUpDown1.Maximum = ;

             numericUpDown1.Minimum = ;

             numericUpDown1.DecimalPlaces = ;

         }

     }

 }