C# WinForm移除非法字符的输入框
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namespace System.Windows.Forms
{using System.ComponentModel;/// <summary>/// 支持移除 非法字符 的输入框。/// </summary>public class RemoveInvalidCharTextBox : TextBox{/// <summary>/// 测试代码：设置 有效字符 为 整数 的字符。/// </summary>[System.Diagnostics.Conditional("DEBUG")][System.Diagnostics.CodeAnalysis.SuppressMessage("", "IDE0017")]public static void TestValidCharAsInteger(){var form = new System.Windows.Forms.Form();var textBox = new RemoveInvalidCharTextBox();textBox.Dock =System.Windows.Forms.DockStyle.Top;textBox.UpdateValidCharAsInteger();form.Controls.Add(textBox);System.Windows.Forms.Application.Run(form);}public RemoveInvalidCharTextBox(){RemoveCharService = new TextBoxBaseRemoveCharService(this);}protected override void OnTextChanged(EventArgs e){RemoveCharService?.OnTextChangedBefore();base.OnTextChanged(e);}/// <summary>/// 更新 有效字符 为 整数 的字符。/// </summary>public void UpdateValidCharAsInteger(){RemoveCharService.UpdateValidCharAsInteger();}private TextBoxBaseRemoveCharService RemoveCharService { get; set; }/// <summary>/// 禁止移除非法字符。/// </summary>[Browsable(false)][EditorBrowsable(EditorBrowsableState.Never)][DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)][DefaultValue(false)]public bool DisabledRemoveInvalidChars{get { return RemoveCharService.DisabledRemoveInvalidChars; }set { RemoveCharService.DisabledRemoveInvalidChars = value; }}}}namespace System.Windows.Forms
{using System.Collections.Generic;using System.ComponentModel;using System.Text;/// <summary>/// 移除非法字符的服务。/// </summary>public class TextBoxBaseRemoveCharService{public TextBoxBaseRemoveCharService(TextBoxBase textBox){this.TextBox = textBox;}#region 初始化函数。/// <summary>/// 更新 有效字符 为 整数 的字符。/// </summary>public void UpdateValidCharAsInteger(){ValidChars = GetIntegerChars();}/// <summary>/// 整数 的 字符。/// </summary>/// <returns></returns>public static IList<char> GetIntegerChars(){return new char[]{'0','1','2','3','4','5','6','7','8','9',};}/// <summary>/// 更新 无效字符 为 换行 的字符。/// </summary>public void UpdateInvalidCharAsNewLine(){InvalidChars = GetNewLineChars();}/// <summary>/// 换行 的字符。/// </summary>/// <returns></returns>public static IList<char> GetNewLineChars(){return new char[]{'\v','\r','\n',};}#endregion 初始化函数。#region 移除非法字符。/// <summary>/// 在 调用 <see cref="TextBoxBase.OnTextChanged(EventArgs)"/> 前执行。 <br />/// 注意：在重载函数中，调用本函数，本函数所属的对象可能为 null 。/// 所以，调用示例为 RemoveCharService?.OnTextChangedBefore()/// </summary>[System.Diagnostics.CodeAnalysis.SuppressMessage("", "S134")]public void OnTextChangedBefore(){var safeValidChars = ValidChars;var hasValidChars = safeValidChars != null && safeValidChars.Count > 0;var safeInvalidChars = InvalidChars;var hasInvalidChars = safeInvalidChars != null && safeInvalidChars.Count > 0;if (DisabledRemoveInvalidChars || (!hasValidChars && !hasInvalidChars)){return;}string oldText = TextBox.Text;if (string.IsNullOrEmpty(oldText)){return;}StringBuilder newBuilder = new StringBuilder(oldText.Length);List<int> removeIndexes = new List<int>(16);int index = -1;foreach (var ch in oldText){++index;if (hasValidChars){if (!safeValidChars.Contains(ch)){removeIndexes.Add(index);}else{newBuilder.Append(ch);}}// 等价 else if (hasInvalidChars)else{if (safeInvalidChars.Contains(ch)){removeIndexes.Add(index);}else{newBuilder.Append(ch);}}}OnTextChangedBeforeCore(oldText, newBuilder, removeIndexes);}private void OnTextChangedBeforeCore(string oldText, StringBuilder newBuilder, List<int> removeIndexes){string newText = newBuilder.ToString();if (newText != oldText){TextBox.SuspendLayout();try{// 处理重命名时，当输入非法字符时，会全选名称的问题。int selectionStartOld = 0;int selectionLengthOld = 0;var isReadySelection = !string.IsNullOrEmpty(newText) &&ReadySelect(out selectionStartOld, out selectionLengthOld);TextBox.Text = newText;// 处理重命名时，当输入非法字符时，会全选名称的问题。if (isReadySelection){selectionLengthOld -= MatchIndexCount(removeIndexes, selectionStartOld - 1, selectionStartOld + selectionLengthOld);selectionStartOld -= MatchIndexCount(removeIndexes, -1, selectionStartOld);GetSafeSelect(newText.Length, ref selectionStartOld, ref selectionLengthOld);UpdateSelect(selectionStartOld, selectionLengthOld);}}finally{TextBox.ResumeLayout();}}}private int MatchIndexCount(IList<int> indexList, int minIndex, int maxIndex){int count = 0;foreach (var index in indexList){if (index > minIndex && index < maxIndex){++count;}}return count;}private bool ReadySelect(out int selectionStart, out int selectionLength){bool isSuccessCompleted;try{selectionStart = TextBox.SelectionStart;selectionLength = TextBox.SelectionLength;isSuccessCompleted = true;}catch (Exception ex){TraceException("Ready selection exception: ", ex);selectionStart = 0;selectionLength = 0;isSuccessCompleted = false;}return isSuccessCompleted;}private void UpdateSelect(int selectionStart, int selectionLength){try{TextBox.Select(selectionStart, selectionLength);}catch (Exception ex){TraceException("Update selection exception: ", ex);}}private void GetSafeSelect(int length, ref int selectionStart, ref int selectionLength){if (selectionStart > length){selectionStart = length;}if (selectionLength > length){selectionLength = length;}}#endregion 移除非法字符。private static void TraceException(string message, Exception ex){System.Diagnostics.Trace.WriteLineIf(true, message + ex);}/// <summary>/// 禁止移除非法字符。/// </summary>[Browsable(false)][EditorBrowsable(EditorBrowsableState.Never)][DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)][DefaultValue(false)]public bool DisabledRemoveInvalidChars { get; set; }/// <summary>/// 有效字符。 <br />/// 注意：<see cref="ValidChars"/> 和 <see cref="InvalidChars"/> 最多一个不为 null 。/// </summary>[Browsable(false)][EditorBrowsable(EditorBrowsableState.Never)][DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)][DefaultValue(null)]private IList<char> ValidChars{get { return validChars; }set{if (validChars != value){if (value != null){InvalidChars = null;}validChars = value;}}}private IList<char> validChars;/// <summary>/// 无效字符。 <br />/// 注意：<see cref="ValidChars"/> 和 <see cref="InvalidChars"/> 最多一个不为 null 。/// </summary>[Browsable(false)][EditorBrowsable(EditorBrowsableState.Never)][DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)][DefaultValue(null)]private IList<char> InvalidChars{get { return invalidChars; }set{if (invalidChars != value){if (value != null){ValidChars = null;}invalidChars = value;}}}private IList<char> invalidChars;private TextBoxBase TextBox { get; set; }}}