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

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[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
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

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原文地址：https://www.cnblogs.com/volnet/p/574393.html