（二十八）c#Winform自定义控件-文本框（一） - 好文

前提

入行已经7,8年了，一直想做一套漂亮点的自定义控件，于是就有了本系列文章。

开源地址：https://gitee.com/kwwwvagaa/net_winform_custom_control
<https://gitee.com/kwwwvagaa/net_winform_custom_control>

如果觉得写的还行，请点个 star 支持一下吧

欢迎前来交流探讨：企鹅群568015492 <https://shang.qq.com/wpa/qunwpa?
idkey=6e08741ef16fe53bf0314c1c9e336c4f626047943a8b76bac062361bab6b4f8d>

目录

https://www.cnblogs.com/bfyx/p/11364884.html
<https://www.cnblogs.com/bfyx/p/11364884.html>

准备工作

终于到文本框了，文本框将包含原文本框扩展，透明文本框，数字输入文本框，带边框文本框

本文将讲解原文本框扩展，主要增加水印和输入控制

开始

添加一个组件，命名TextBoxEx，继承TextBox

属性
1 private bool blnFocus = false; 2 3 private string _promptText = string
.Empty; 4 5 private Font _promptFont = new Font("微软雅黑", 15f,
FontStyle.Regular, GraphicsUnit.Pixel); 6 7 private Color _promptColor =
Color.Gray; 8 9 private Rectangle _myRectangle = Rectangle.FromLTRB(1, 3, 1000,
3); 10 11 private TextInputType _inputType = TextInputType.NotControl; 12 13
private string _regexPattern = ""; 14 15 private string m_strOldValue = string
.Empty; 16 17 private decimal _maxValue = 1000000m; 18 19 private decimal
_minValue = -1000000m; 20 21 private int _decLength = 2; 22 23 /// <summary>
24 /// 水印文字 25 /// </summary> 26 [Description("水印文字"), Category("自定义")] 27
public string PromptText 28 { 29 get 30 { 31 return this._promptText; 32
} 33 set 34 { 35 this._promptText = value; 36 this.OnPaint(null); 37 }
38 } 39 40 [Description("水印字体"), Category("自定义")] 41 public Font PromptFont
42 { 43 get 44 { 45 return this._promptFont; 46 } 47 set 48 { 49
this._promptFont = value; 50 } 51 } 52 53 [Description("水印颜色"), Category("
自定义")] 54 public Color PromptColor 55 { 56 get 57 { 58 return this
._promptColor; 59 } 60 set 61 { 62 this._promptColor = value; 63 } 64 }
65 66 public Rectangle MyRectangle 67 { 68 get; 69 set; 70 } 71 72
public string OldText 73 { 74 get; 75 set; 76 } 77 78 [Description("
获取或设置一个值，该值指示文本框中的文本输入类型。")] 79 public TextInputType InputType 80 { 81 get
82 { 83 return this._inputType; 84 } 85 set 86 { 87 this._inputType =
value; 88 if (value != TextInputType.NotControl) 89 { 90 TextChanged -= new
EventHandler(this.TextBoxEx_TextChanged); 91 TextChanged += new EventHandler(
this.TextBoxEx_TextChanged); 92 } 93 else 94 { 95 TextChanged -= new
EventHandler(this.TextBoxEx_TextChanged); 96 } 97 } 98 } 99 /// <summary>
100 /// 获取或设置一个值，该值指示当输入类型InputType=Regex时，使用的正则表达式。 101 /// </summary> 102
[Description("获取或设置一个值，该值指示当输入类型InputType=Regex时，使用的正则表达式。")] 103 public string
RegexPattern104 { 105 get 106 { 107 return this._regexPattern; 108 } 109 set
110 { 111 this._regexPattern = value; 112 } 113 } 114 /// <summary> 115 ///
当InputType为数字类型时，能输入的最大值116 /// </summary> 117 [Description("
当InputType为数字类型时，能输入的最大值。")] 118 public decimal MaxValue 119 { 120 get 121 {
122 return this._maxValue; 123 } 124 set 125 { 126 this._maxValue = value; 127
}128 } 129 /// <summary> 130 /// 当InputType为数字类型时，能输入的最小值 131 /// </summary>
132 [Description("当InputType为数字类型时，能输入的最小值。")] 133 public decimal MinValue 134
{135 get 136 { 137 return this._minValue; 138 } 139 set 140 { 141 this
._minValue = value; 142 } 143 } 144 /// <summary> 145 ///
当InputType为数字类型时，能输入的最小值146 /// </summary> 147 [Description("
当InputType为数字类型时，小数位数。")] 148 public int DecLength 149 { 150 get 151 { 152
return this._decLength; 153 } 154 set 155 { 156 this._decLength = value; 157
}158 }
一些事件
1 void TextBoxEx_KeyPress(object sender, KeyPressEventArgs e) 2 { 3 //以下代码
取消按下回车或esc的“叮”声 4 if (e.KeyChar == System.Convert.ToChar(13) || e.KeyChar ==
System.Convert.ToChar(27)) 5 { 6 e.Handled = true; 7 } 8 } 9 10 private
void TextBoxEx_MouseUp(object sender, MouseEventArgs e) 11 { 12 if (this
.blnFocus)13 { 14 base.SelectAll(); 15 this.blnFocus = false; 16 } 17 } 18 19
private void TextBoxEx_GotFocus(object sender, EventArgs e) 20 { 21 this
.blnFocus =true; 22 base.SelectAll(); 23 } 24 25 private void
TextBoxEx_TextChanged(object sender, EventArgs e) 26 { 27 if (this.Text == "")
28 { 29 this.m_strOldValue = this.Text; 30 } 31 else if (this.m_strOldValue !=
this.Text) 32 { 33 if (!ControlHelper.CheckInputType(this.Text, this
._inputType,this._maxValue, this._minValue, this._decLength, this
._regexPattern))34 { 35 int num = base.SelectionStart; 36 if (this
.m_strOldValue.Length <this.Text.Length) 37 { 38 num--; 39 } 40 else 41 { 42
num++; 43 } 44 base.TextChanged -= new EventHandler(this
.TextBoxEx_TextChanged);45 this.Text = this.m_strOldValue; 46 base.TextChanged
+=new EventHandler(this.TextBoxEx_TextChanged); 47 if (num < 0) 48 { 49 num = 0
;50 } 51 base.SelectionStart = num; 52 } 53 else 54 { 55 this.m_strOldValue =
this.Text; 56 } 57 } 58 }
重绘
1 protected override void OnPaint(PaintEventArgs e) 2 { 3 base.OnPaint(e);
4 if (string.IsNullOrEmpty(this.Text) && !string.IsNullOrEmpty(this
._promptText)) 5 { 6 if (e == null) 7 { 8 using (Graphics graphics =
Graphics.FromHwnd(base.Handle)) 9 { 10 if (this.Text.Length == 0 && !string
.IsNullOrEmpty(this.PromptText)) 11 { 12 TextFormatFlags textFormatFlags =
TextFormatFlags.EndEllipsis | TextFormatFlags.VerticalCenter; 13 if (this
.RightToLeft == RightToLeft.Yes) 14 { 15 textFormatFlags |=
(TextFormatFlags.Right | TextFormatFlags.RightToLeft); 16 } 17
TextRenderer.DrawText(graphics,this.PromptText, this._promptFont, base
.ClientRectangle,this._promptColor, textFormatFlags); 18 } 19 } 20 } 21 } 22
}
下面是完整代码
1 // 版权所有黄正辉交流群：568015492 QQ：623128629 2 // 文件名称：TextBoxEx.cs 3 //
创建日期：2019-08-15 16:03:44 4 // 功能描述：TextBox 5 // 项目地址：
https://gitee.com/kwwwvagaa/net_winform_custom_control 6 using System; 7 using
System.Collections.Generic; 8 using System.ComponentModel; 9 using
System.Diagnostics; 10 using System.Drawing; 11 using System.Linq; 12 using
System.Text; 13 using System.Windows.Forms; 14 15 namespace
HZH_Controls.Controls 16 { 17 public partial class TextBoxEx : TextBox 18 {
19 private bool blnFocus = false; 20 21 private string _promptText = string
.Empty; 22 23 private Font _promptFont = new Font("微软雅黑", 15f,
FontStyle.Regular, GraphicsUnit.Pixel); 24 25 private Color _promptColor =
Color.Gray; 26 27 private Rectangle _myRectangle = Rectangle.FromLTRB(1, 3,
1000, 3); 28 29 private TextInputType _inputType = TextInputType.NotControl;
30 31 private string _regexPattern = ""; 32 33 private string m_strOldValue =
string.Empty; 34 35 private decimal _maxValue = 1000000m; 36 37 private
decimal _minValue = -1000000m; 38 39 private int _decLength = 2; 40 41 ///
<summary> 42 /// 水印文字 43 /// </summary> 44 [Description("水印文字"), Category("
自定义")] 45 public string PromptText 46 { 47 get 48 { 49 return this
._promptText; 50 } 51 set 52 { 53 this._promptText = value; 54 this
.OnPaint(null); 55 } 56 } 57 58 [Description("水印字体"), Category("自定义")] 59
public Font PromptFont 60 { 61 get 62 { 63 return this._promptFont; 64 }
65 set 66 { 67 this._promptFont = value; 68 } 69 } 70 71 [Description(
"水印颜色"), Category("自定义")] 72 public Color PromptColor 73 { 74 get 75 { 76
return this._promptColor; 77 } 78 set 79 { 80 this._promptColor = value;
81 } 82 } 83 84 public Rectangle MyRectangle 85 { 86 get; 87 set; 88
} 89 90 public string OldText 91 { 92 get; 93 set; 94 } 95 96
[Description("获取或设置一个值，该值指示文本框中的文本输入类型。")] 97 public TextInputType InputType
98 { 99 get 100 { 101 return this._inputType; 102 } 103 set 104 { 105 this
._inputType = value; 106 if (value != TextInputType.NotControl) 107 { 108
TextChanged -=new EventHandler(this.TextBoxEx_TextChanged); 109 TextChanged +=
new EventHandler(this.TextBoxEx_TextChanged); 110 } 111 else 112 { 113
TextChanged -=new EventHandler(this.TextBoxEx_TextChanged); 114 } 115 } 116 }
117 /// <summary> 118 /// 获取或设置一个值，该值指示当输入类型InputType=Regex时，使用的正则表达式。 119 ///
</summary> 120 [Description("获取或设置一个值，该值指示当输入类型InputType=Regex时，使用的正则表达式。")] 121
public string RegexPattern 122 { 123 get 124 { 125 return this._regexPattern;
126 } 127 set 128 { 129 this._regexPattern = value; 130 } 131 } 132 ///
<summary> 133 /// 当InputType为数字类型时，能输入的最大值 134 /// </summary> 135 [Description("
当InputType为数字类型时，能输入的最大值。")] 136 public decimal MaxValue 137 { 138 get 139 {
140 return this._maxValue; 141 } 142 set 143 { 144 this._maxValue = value; 145
}146 } 147 /// <summary> 148 /// 当InputType为数字类型时，能输入的最小值 149 /// </summary>
150 [Description("当InputType为数字类型时，能输入的最小值。")] 151 public decimal MinValue 152
{153 get 154 { 155 return this._minValue; 156 } 157 set 158 { 159 this
._minValue = value; 160 } 161 } 162 /// <summary> 163 ///
当InputType为数字类型时，能输入的最小值164 /// </summary> 165 [Description("
当InputType为数字类型时，小数位数。")] 166 public int DecLength 167 { 168 get 169 { 170
return this._decLength; 171 } 172 set 173 { 174 this._decLength = value; 175
}176 } 177 178 public TextBoxEx() 179 { 180 this.InitializeComponent(); 181
base.GotFocus += new EventHandler(this.TextBoxEx_GotFocus); 182 base.MouseUp +=
new MouseEventHandler(this.TextBoxEx_MouseUp); 183 base.KeyPress +=
TextBoxEx_KeyPress;184 } 185 186 void TextBoxEx_KeyPress(object sender,
KeyPressEventArgs e)187 { 188 //以下代码取消按下回车或esc的“叮”声 189 if (e.KeyChar ==
System.Convert.ToChar(13) || e.KeyChar == System.Convert.ToChar(27)) 190 { 191
e.Handled =true; 192 } 193 } 194 195 private void TextBoxEx_MouseUp(object
sender, MouseEventArgs e)196 { 197 if (this.blnFocus) 198 { 199 base
.SelectAll();200 this.blnFocus = false; 201 } 202 } 203 204 private void
TextBoxEx_GotFocus(object sender, EventArgs e) 205 { 206 this.blnFocus = true;
207 base.SelectAll(); 208 } 209 210 private void TextBoxEx_TextChanged(object
sender, EventArgs e)211 { 212 if (this.Text == "") 213 { 214 this
.m_strOldValue =this.Text; 215 } 216 else if (this.m_strOldValue != this.Text)
217 { 218 if (!ControlHelper.CheckInputType(this.Text, this._inputType, this
._maxValue,this._minValue, this._decLength, this._regexPattern)) 219 { 220 int
num =base.SelectionStart; 221 if (this.m_strOldValue.Length < this.Text.Length)
222 { 223 num--; 224 } 225 else 226 { 227 num++; 228 } 229 base.TextChanged
-=new EventHandler(this.TextBoxEx_TextChanged); 230 this.Text = this
.m_strOldValue;231 base.TextChanged += new EventHandler(this
.TextBoxEx_TextChanged);232 if (num < 0) 233 { 234 num = 0; 235 } 236 base
.SelectionStart = num; 237 } 238 else 239 { 240 this.m_strOldValue = this
.Text;241 } 242 } 243 } 244 245 protected override void
OnPaint(PaintEventArgs e)246 { 247 base.OnPaint(e); 248 if (string
.IsNullOrEmpty(this.Text) && !string.IsNullOrEmpty(this._promptText)) 249 { 250
if (e == null) 251 { 252 using (Graphics graphics = Graphics.FromHwnd(base
.Handle))253 { 254 if (this.Text.Length == 0 && !string.IsNullOrEmpty(this
.PromptText))255 { 256 TextFormatFlags textFormatFlags =
TextFormatFlags.EndEllipsis | TextFormatFlags.VerticalCenter; 257 if (this
.RightToLeft == RightToLeft.Yes) 258 { 259 textFormatFlags |=
(TextFormatFlags.Right | TextFormatFlags.RightToLeft); 260 } 261
TextRenderer.DrawText(graphics,this.PromptText, this._promptFont, base
.ClientRectangle,this._promptColor, textFormatFlags); 262 } 263 } 264 } 265
}266 } 267 268 protected override void WndProc(ref Message m) 269 { 270 base
.WndProc(ref m); 271 if (m.Msg == 15 || m.Msg == 7 || m.Msg == 8) 272 { 273
this.OnPaint(null); 274 } 275 } 276 277 protected override void
OnTextChanged(EventArgs e)278 { 279 base.OnTextChanged(e); 280 base
.Invalidate();281 } 282 } 283 } View Code
用处及效果

用处：需要控制输入，需要显示水印

最后的话

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