[C#][SAMPLE][CODE][Control]TextBox和Validating事件的相关处理

[示例出处]：本示例来自《C#入门经典》第三版中文版，P342-P348
[示例涉及]：
1、TextBox控件的基本使用
2、Validating事件的使用
3、多委托处理同一事件方法
[示例代码]：2文件(其余默认)

Form1.Designer.cs

  1namespace WA_TextBoxTest
  2{
  3    partial class Form1
  4    {
  5        /**//// <summary>
  6        /// 必需的设计器变量。
  7        /// </summary>
  8        private System.ComponentModel.IContainer components = null;
  9
 10        /**//// <summary>
 11        /// 清理所有正在使用的资源。
 12        /// </summary>
 13        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
 14        protected override void Dispose(bool disposing)
 15        {
 16            if (disposing && (components != null))
 17            {
 18                components.Dispose();
 19            }
 20            base.Dispose(disposing);
 21        }
 22
 23        Windows 窗体设计器生成的代码#region Windows 窗体设计器生成的代码
 24
 25        /**//// <summary>
 26        /// 设计器支持所需的方法 - 不要
 27        /// 使用代码编辑器修改此方法的内容。
 28        /// </summary>
 29        private void InitializeComponent()
 30        {
 31            this.label1 = new System.Windows.Forms.Label();
 32            this.label2 = new System.Windows.Forms.Label();
 33            this.textBoxName = new System.Windows.Forms.TextBox();
 34            this.textBoxAddress = new System.Windows.Forms.TextBox();
 35            this.textBoxOccupation = new System.Windows.Forms.TextBox();
 36            this.textBoxAge = new System.Windows.Forms.TextBox();
 37            this.textBoxOutput = new System.Windows.Forms.TextBox();
 38            this.label3 = new System.Windows.Forms.Label();
 39            this.label4 = new System.Windows.Forms.Label();
 40            this.label5 = new System.Windows.Forms.Label();
 41            this.buttonOK = new System.Windows.Forms.Button();
 42            this.buttonHelp = new System.Windows.Forms.Button();
 43            this.SuspendLayout();
 44            // 
 45            // label1
 46            // 
 47            this.label1.AutoSize = true;
 48            this.label1.Location = new System.Drawing.Point(26, 27);
 49            this.label1.Name = "label1";
 50            this.label1.Size = new System.Drawing.Size(59, 12);
 51            this.label1.TabIndex = 0;
 52            this.label1.Text = "labelName";
 53            // 
 54            // label2
 55            // 
 56            this.label2.AutoSize = true;
 57            this.label2.Location = new System.Drawing.Point(26, 53);
 58            this.label2.Name = "label2";
 59            this.label2.Size = new System.Drawing.Size(77, 12);
 60            this.label2.TabIndex = 1;
 61            this.label2.Text = "labelAddress";
 62            // 
 63            // textBoxName
 64            // 
 65            this.textBoxName.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
 66                        | System.Windows.Forms.AnchorStyles.Right)));
 67            this.textBoxName.Location = new System.Drawing.Point(127, 24);
 68            this.textBoxName.Name = "textBoxName";
 69            this.textBoxName.Size = new System.Drawing.Size(317, 21);
 70            this.textBoxName.TabIndex = 2;
 71            // 
 72            // textBoxAddress
 73            // 
 74            this.textBoxAddress.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
 75                        | System.Windows.Forms.AnchorStyles.Right)));
 76            this.textBoxAddress.Location = new System.Drawing.Point(127, 50);
 77            this.textBoxAddress.Multiline = true;
 78            this.textBoxAddress.Name = "textBoxAddress";
 79            this.textBoxAddress.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
 80            this.textBoxAddress.Size = new System.Drawing.Size(317, 102);
 81            this.textBoxAddress.TabIndex = 2;
 82            // 
 83            // textBoxOccupation
 84            // 
 85            this.textBoxOccupation.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
 86                        | System.Windows.Forms.AnchorStyles.Right)));
 87            this.textBoxOccupation.Location = new System.Drawing.Point(127, 158);
 88            this.textBoxOccupation.Name = "textBoxOccupation";
 89            this.textBoxOccupation.Size = new System.Drawing.Size(317, 21);
 90            this.textBoxOccupation.TabIndex = 3;
 91            this.textBoxOccupation.Validating += new System.ComponentModel.CancelEventHandler(this.textBoxOccupation_Validating);
 92            // 
 93            // textBoxAge
 94            // 
 95            this.textBoxAge.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
 96                        | System.Windows.Forms.AnchorStyles.Right)));
 97            this.textBoxAge.Location = new System.Drawing.Point(127, 193);
 98            this.textBoxAge.Name = "textBoxAge";
 99            this.textBoxAge.Size = new System.Drawing.Size(99, 21);
100            this.textBoxAge.TabIndex = 4;
101            this.textBoxAge.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBoxAge_KeyPress);
102            // 
103            // textBoxOutput
104            // 
105            this.textBoxOutput.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
106                        | System.Windows.Forms.AnchorStyles.Left)
107                        | System.Windows.Forms.AnchorStyles.Right)));
108            this.textBoxOutput.Location = new System.Drawing.Point(28, 243);
109            this.textBoxOutput.Multiline = true;
110            this.textBoxOutput.Name = "textBoxOutput";
111            this.textBoxOutput.ReadOnly = true;
112            this.textBoxOutput.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
113            this.textBoxOutput.Size = new System.Drawing.Size(416, 150);
114            this.textBoxOutput.TabIndex = 5;
115            // 
116            // label3
117            // 
118            this.label3.AutoSize = true;
119            this.label3.Location = new System.Drawing.Point(26, 161);
120            this.label3.Name = "label3";
121            this.label3.Size = new System.Drawing.Size(95, 12);
122            this.label3.TabIndex = 6;
123            this.label3.Text = "labelOccupation";
124            // 
125            // label4
126            // 
127            this.label4.AutoSize = true;
128            this.label4.Location = new System.Drawing.Point(26, 196);
129            this.label4.Name = "label4";
130            this.label4.Size = new System.Drawing.Size(53, 12);
131            this.label4.TabIndex = 7;
132            this.label4.Text = "labelAge";
133            // 
134            // label5
135            // 
136            this.label5.AutoSize = true;
137            this.label5.Location = new System.Drawing.Point(26, 228);
138            this.label5.Name = "label5";
139            this.label5.Size = new System.Drawing.Size(71, 12);
140            this.label5.TabIndex = 8;
141            this.label5.Text = "labelOutput";
142            // 
143            // buttonOK
144            // 
145            this.buttonOK.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
146            this.buttonOK.Location = new System.Drawing.Point(458, 18);
147            this.buttonOK.Name = "buttonOK";
148            this.buttonOK.Size = new System.Drawing.Size(82, 21);
149            this.buttonOK.TabIndex = 9;
150            this.buttonOK.Text = "OK";
151            this.buttonOK.UseVisualStyleBackColor = true;
152            this.buttonOK.Click += new System.EventHandler(this.buttonOK_Click);
153            // 
154            // buttonHelp
155            // 
156            this.buttonHelp.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
157            this.buttonHelp.CausesValidation = false;
158            this.buttonHelp.Location = new System.Drawing.Point(458, 43);
159            this.buttonHelp.Name = "buttonHelp";
160            this.buttonHelp.Size = new System.Drawing.Size(82, 21);
161            this.buttonHelp.TabIndex = 10;
162            this.buttonHelp.Text = "Help";
163            this.buttonHelp.UseVisualStyleBackColor = true;
164            this.buttonHelp.Click += new System.EventHandler(this.buttonHelp_Click);
165            // 
166            // Form1
167            // 
168            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
169            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
170            this.ClientSize = new System.Drawing.Size(561, 405);
171            this.Controls.Add(this.buttonHelp);
172            this.Controls.Add(this.buttonOK);
173            this.Controls.Add(this.label5);
174            this.Controls.Add(this.label4);
175            this.Controls.Add(this.label3);
176            this.Controls.Add(this.textBoxOutput);
177            this.Controls.Add(this.textBoxAge);
178            this.Controls.Add(this.textBoxOccupation);
179            this.Controls.Add(this.textBoxAddress);
180            this.Controls.Add(this.textBoxName);
181            this.Controls.Add(this.label2);
182            this.Controls.Add(this.label1);
183            this.Name = "Form1";
184            this.Text = "Form1";
185            this.Validating += new System.ComponentModel.CancelEventHandler(this.textBoxEmpty_Validating);
186            this.ResumeLayout(false);
187            this.PerformLayout();
188
189        }
190
191        #endregion
192
193        private System.Windows.Forms.Label label1;
194        private System.Windows.Forms.Label label2;
195        private System.Windows.Forms.TextBox textBoxName;
196        private System.Windows.Forms.TextBox textBoxAddress;
197        private System.Windows.Forms.TextBox textBoxOccupation;
198        private System.Windows.Forms.TextBox textBoxAge;
199        private System.Windows.Forms.TextBox textBoxOutput;
200        private System.Windows.Forms.Label label3;
201        private System.Windows.Forms.Label label4;
202        private System.Windows.Forms.Label label5;
203        private System.Windows.Forms.Button buttonOK;
204        private System.Windows.Forms.Button buttonHelp;
205    }
206}
207
208

Form1.cs

  1using System;
  2using System.Collections.Generic;
  3using System.ComponentModel;
  4using System.Data;
  5using System.Drawing;
  6using System.Text;
  7using System.Windows.Forms;
  8
  9namespace WA_TextBoxTest
 10{
 11    public partial class Form1 : Form
 12    {
 13        public Form1()
 14        {
 15            InitializeComponent();
 16            this.buttonOK.Enabled = false;
 17
 18            //Tag values for testing if the data is valid.
 19            this.textBoxName.Tag = false;
 20            this.textBoxAddress.Tag = false;
 21            this.textBoxAge.Tag = false;
 22            this.textBoxOccupation.Tag = false;
 23
 24            //订阅事件Subscriptions to events
 25            this.textBoxName.Validating += new CancelEventHandler(this.textBoxEmpty_Validating);
 26            this.textBoxAddress.Validating += new CancelEventHandler(this.textBoxEmpty_Validating);
 27            this.textBoxOccupation.Validating += new CancelEventHandler(this.textBoxOccupation_Validating);
 28            this.textBoxAge.Validating += new CancelEventHandler(this.textBoxEmpty_Validating);
 29
 30            //当控件中文本发生改变，就激发TextChanged事件。
 31            this.textBoxName.TextChanged +=new EventHandler(textBox_TextChanged);
 32            this.textBoxAddress.TextChanged+=new EventHandler(textBox_TextChanged);
 33            this.textBoxOccupation.TextChanged+=new EventHandler(textBox_TextChanged);
 34            this.textBoxAge.TextChanged += new EventHandler(textBox_TextChanged);
 35        }
 36
 37        private void buttonOK_Click(object sender, EventArgs e)
 38        {
 39            //No testing for invalid values are made ,as that should not be necessary
 40            string output;
 41            
 42            //Concatenate the text values of for TextBoxes.
 43            output = "Name:" + this.textBoxName.Text + "\r\n";
 44            output += "Address:" + this.textBoxAddress.Text + "\r\n";
 45            output += "Occupation:" + this.textBoxOccupation.Text + "\r\n";
 46            output += "Age:" + this.textBoxAge.Text;
 47 
 48            //Insert the new text.
 49            this.textBoxOutput.Text = output;
 50        }
 51
 52        private void buttonHelp_Click(object sender, EventArgs e)
 53        {
 54            //Write a short description of each TextBox in the Output TextBox.
 55            string output;
 56
 57            output = "Name=Your name\r\n";
 58            output += "Address=Your address\r\n";
 59            output += "Occupation=Only allowed value is 'Programmer'\r\n";
 60            output += "Age=Your age";
 61
 62            //Insert the new text.
 63            this.textBoxOutput.Text = output;
 64        }
 65
 66        private void textBoxEmpty_Validating(object sender, CancelEventArgs e)
 67        {
 68            //我们知道这个sender是一个对话框，所以我们将他们强制转换为TextBox
 69            TextBox tb = (TextBox)sender;
 70
 71            //如果对话框是空的话我们设置TextBox背景色为红色来象征问题。
 72            //如果控件有valid信息，我们就使用控件的Tag值来指出。
 73            if (tb.Text.Length == 0)
 74            {
 75                tb.BackColor = Color.Red;
 76                tb.Tag = false;
 77                //在这个例子中我们不想取消further processing
 78                //但是如果我们想要这么做的话，我们只需要添加以下一行：
 79                //e.Cancel=true;
 80            }
 81            else
 82            {
 83                this.BackColor = SystemColors.Window;
 84                tb.Tag = true;
 85            }
 86            //Finally ,we call ValidateOK which will set the value of the OK button.
 87            ValidateOK();
 88        }
 89
 90        private void textBoxOccupation_Validating(object sender, CancelEventArgs e)
 91        {
 92            //Cast the sender object to a textBox
 93            TextBox tb = (TextBox)sender;
 94            
 95            //Check if the values are correct
 96            if (tb.Text.CompareTo("Programmer") == 0 || tb.Text.Length == 0)
 97            {
 98                tb.Tag = true;
 99                tb.BackColor = Color.Red;
100            }
101            else
102            {
103                tb.Tag = false;
104                tb.BackColor = SystemColors.Window;
105            }
106
107            //Set the state of the OK button
108            ValidateOK();
109        }
110
111        private void textBoxAge_KeyPress(object sender, KeyPressEventArgs e)
112        {
113            if ((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8)
114            {
115                e.Handled = true;   //Remove the character
116                //等于true告诉用户不应该对字符进行任何操作
117            }
118        }
119
120        private void textBox_TextChanged(object sender, EventArgs e)
121        {
122            //Cast the sender object to a TextBox
123            TextBox tb = (TextBox)sender;
124
125            //Test if the data is valid and set the tag and back ground color accordingly.
126            if (tb.Text.Length == 0 && tb != textBoxOccupation)
127            {
128                tb.Tag = false;
129                tb.BackColor = Color.Red;
130            }
131            else if (tb == textBoxOccupation && (tb.Text.Length != 0 && tb.Text.CompareTo("Programmer") != 0))
132            {
133                //Don't set the color here,as it will color change while the user is typing
134                tb.Tag = false;
135            }
136            else
137            {
138                tb.Tag = true;
139                tb.BackColor = SystemColors.Window;
140            }
141
142            //Call ValidateOK to set the OK button
143            ValidateOK();
144        }
145
146        private void ValidateOK()
147        { 
148            //Set the OK button to enabled if all the Tags are true
149            this.buttonOK.Enabled = ((bool)(this.textBoxName.Tag) &&
150                (bool)(this.textBoxAge.Tag) &&
151                (bool)(this.textBoxAddress.Tag) &&
152                (bool)(this.textBoxOccupation.Tag));
153        }
154    }
155}

[示例说明]：
1、开发语言：C#
2、开发环境：Visual Studio.Net 2005 Team suite
3、开发模板：C#.net项目->Windows应用程序