C#判斷一個string是否可以爲數字的幾種解決方案

 

 

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方案一：Try...Catch(執行效率不高)view plaincopy to clipboardprint? /// <summary> /// 名稱：IsNumberic /// 功能：判斷輸入的是否是數字 /// 參數：string oText：源文本 /// 返回值：　bool true:是　false:否 /// </summary> /// <param name="oText"></param> /// <returns></returns> private bool IsNumberic(string oText) { try { int var1=Convert.ToInt32 (oText); return true; } catch { return false; } } /// <summary> /// 名稱：IsNumberic /// 功能：判斷輸入的是否是數字 /// 參數：string oText：源文本 /// 返回值：　bool true:是　false:否 /// </summary> /// <param name="oText"></param> /// <returns></returns> private bool IsNumberic(string oText) { try { int var1=Convert.ToInt32 (oText); return true; } catch { return false; } }方案二：正則表達式(推薦) a)view plaincopy to clipboardprint? using System; using System.Text.RegularExpressions; public bool IsNumber(String strNumber) { Regex objNotNumberPattern=new Regex("[^0-9.-]"); Regex objTwoDotPattern=new Regex("[0-9]*[.][0-9]*[.][0-9]*"); Regex objTwoMinusPattern=new Regex("[0-9]*[-][0-9]*[-][0-9]*"); String strValidRealPattern="^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$"; String strValidIntegerPattern="^([-]|[0-9])[0-9]*$"; Regex objNumberPattern =new Regex("(" + strValidRealPattern +")|(" + strValidIntegerPattern + ")"); return !objNotNumberPattern.IsMatch(strNumber) && !objTwoDotPattern.IsMatch(strNumber) && !objTwoMinusPattern.IsMatch(strNumber) && objNumberPattern.IsMatch(strNumber); } using System; using System.Text.RegularExpressions; public bool IsNumber(String strNumber) { Regex objNotNumberPattern=new Regex("[^0-9.-]"); Regex objTwoDotPattern=new Regex("[0-9]*[.][0-9]*[.][0-9]*"); Regex objTwoMinusPattern=new Regex("[0-9]*[-][0-9]*[-][0-9]*"); String strValidRealPattern="^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$"; String strValidIntegerPattern="^([-]|[0-9])[0-9]*$"; Regex objNumberPattern =new Regex("(" + strValidRealPattern +")|(" + strValidIntegerPattern + ")"); return !objNotNumberPattern.IsMatch(strNumber) && !objTwoDotPattern.IsMatch(strNumber) && !objTwoMinusPattern.IsMatch(strNumber) && objNumberPattern.IsMatch(strNumber); }b)view plaincopy to clipboardprint? public static bool IsNumeric(string value) { return Regex.IsMatch(value, @"^[+-]?\d*[.]?\d*$"); } public static bool IsInt(string value) { return Regex.IsMatch(value, @"^[+-]?\d*$"); } public static bool IsUnsign(string value) { return Regex.IsMatch(value, @"^\d*[.]?\d*$"); } public static bool IsNumeric(string value) { return Regex.IsMatch(value, @"^[+-]?\d*[.]?\d*$"); } public static bool IsInt(string value) { return Regex.IsMatch(value, @"^[+-]?\d*$"); } public static bool IsUnsign(string value) { return Regex.IsMatch(value, @"^\d*[.]?\d*$"); }方案三：遍曆 [url=http://www.devdao.com]www.devdao.com[/url] a)view plaincopy to clipboardprint? public bool isnumeric(string str) { char[] ch=new char[str.Length]; ch=str.ToCharArray(); for(int i=0;i<ch.Length;i++) { if(ch[i]<48 || ch[i]>57) return false; } return true; } public bool isnumeric(string str) { char[] ch=new char[str.Length]; ch=str.ToCharArray(); for(int i=0;i<ch.Length;i++) { if(ch[i]<48 || ch[i]>57) return false; } return true; }b)view plaincopy to clipboardprint? public bool IsInteger(string strIn) { bool bolResult=true; if(strIn=="") { bolResult=false; } else { foreach(char Char in strIn) { if(char.IsNumber(Char)) continue; else { bolResult=false; break; } } } return bolResult; } public bool IsInteger(string strIn) { bool bolResult=true; if(strIn=="") { bolResult=false; } else { foreach(char Char in strIn) { if(char.IsNumber(Char)) continue; else { bolResult=false; break; } } } return bolResult; }c)view plaincopy to clipboardprint? public static bool isNumeric(string inString) { inString=inString.Trim(); bool haveNumber=false; bool haveDot=false; for(int i=0;i<inString.Length;i++) { if (Char.IsNumber(inString[i])) { haveNumber=true; } else if(inString[i]=='.') { if (haveDot) { return false; } else { haveDot=true; } } else if(i==0) { if(inString[i]!='+'&&inString[i]!='-') { return false; } } else { return false; } if(i>20) { return false; } } return haveNumber; } } public static bool isNumeric(string inString) { inString=inString.Trim(); bool haveNumber=false; bool haveDot=false; for(int i=0;i<inString.Length;i++) { if (Char.IsNumber(inString[i])) { haveNumber=true; } else if(inString[i]=='.') { if (haveDot) { return false; } else { haveDot=true; } } else if(i==0) { if(inString[i]!='+'&&inString[i]!='-') { return false; } } else { return false; } if(i>20) { return false; } } return haveNumber; } }方案四：改寫vb的IsNumeric源代碼(執行效率不高)view plaincopy to clipboardprint? //主調函數 public static bool IsNumeric(object Expression) { bool flag1; IConvertible convertible1 = null; if (Expression is IConvertible) { convertible1 = (IConvertible) Expression; } if (convertible1 == null) { if (Expression is char[]) { Expression = new string((char[]) Expression); } else { return false; } } TypeCode code1 = convertible1.GetTypeCode(); if ((code1 != TypeCode.String) && (code1 != TypeCode.Char)) { return Utils.IsNumericTypeCode(code1); } string text1 = convertible1.ToString(null); try { long num2; if (!StringType.IsHexOrOctValue(text1, ref num2)) { double num1; return DoubleType.TryParse(text1, ref num1); } flag1 = true; } catch (Exception) { flag1 = false; } return flag1; } //子函數 // return Utils.IsNumericTypeCode(code1); internal static bool IsNumericTypeCode(TypeCode TypCode) { switch (TypCode) { case TypeCode.Boolean: case TypeCode.Byte: case TypeCode.Int16: case TypeCode.Int32: case TypeCode.Int64: case TypeCode.Single: case TypeCode.Double: case TypeCode.Decimal: { return true; } case TypeCode.Char: case TypeCode.SByte: case TypeCode.UInt16: case TypeCode.UInt32: case TypeCode.UInt64: { break; } } return false; } //----------------- //StringType.IsHexOrOctValue(text1, ref num2)) internal static bool IsHexOrOctValue(string Value, ref long i64Value) { int num1; int num2 = Value.Length; while (num1 < num2) { char ch1 = Value[num1]; if (ch1 == '&') { ch1 = char.ToLower(Value[num1 + 1], CultureInfo.InvariantCulture); string text1 = StringType.ToHalfwidthNumbers(Value.Substring(num1 + 2)); if (ch1 == 'h') { i64Value = Convert.ToInt64(text1, 0x10); } else if (ch1 == 'o') { i64Value = Convert.ToInt64(text1, 8); } else { throw new FormatException(); } return true; } if ((ch1 != ' ') && (ch1 != '\u3000')) { return false; } num1++; } return false; } //---------------------------------------------------- // DoubleType.TryParse(text1, ref num1); internal static bool TryParse(string Value, ref double Result) { bool flag1; CultureInfo info1 = Utils.GetCultureInfo(); NumberFormatInfo info3 = info1.NumberFormat; NumberFormatInfo info2 = DecimalType.GetNormalizedNumberFormat(info3); Value = StringType.ToHalfwidthNumbers(Value, info1); if (info3 == info2) { return double.TryParse(Value, NumberStyles.Any, info2, out Result); } try { Result = double.Parse(Value, NumberStyles.Any, info2); flag1 = true; } catch (FormatException) { flag1 = double.TryParse(Value, NumberStyles.Any, info3, out Result); } catch (Exception) { flag1 = false; } return flag1; } //主調函數 public static bool IsNumeric(object Expression) { bool flag1; IConvertible convertible1 = null; if (Expression is IConvertible) { convertible1 = (IConvertible) Expression; } if (convertible1 == null) { if (Expression is char[]) { Expression = new string((char[]) Expression); } else { return false; } } TypeCode code1 = convertible1.GetTypeCode(); if ((code1 != TypeCode.String) && (code1 != TypeCode.Char)) { return Utils.IsNumericTypeCode(code1); } string text1 = convertible1.ToString(null); try { long num2; if (!StringType.IsHexOrOctValue(text1, ref num2)) { double num1; return DoubleType.TryParse(text1, ref num1); } flag1 = true; } catch (Exception) { flag1 = false; } return flag1; } //子函數 // return Utils.IsNumericTypeCode(code1); internal static bool IsNumericTypeCode(TypeCode TypCode) { switch (TypCode) { case TypeCode.Boolean: case TypeCode.Byte: case TypeCode.Int16: case TypeCode.Int32: case TypeCode.Int64: case TypeCode.Single: case TypeCode.Double: case TypeCode.Decimal: { return true; } case TypeCode.Char: case TypeCode.SByte: case TypeCode.UInt16: case TypeCode.UInt32: case TypeCode.UInt64: { break; } } return false; } //----------------- //StringType.IsHexOrOctValue(text1, ref num2)) internal static bool IsHexOrOctValue(string Value, ref long i64Value) { int num1; int num2 = Value.Length; while (num1 < num2) { char ch1 = Value[num1]; if (ch1 == '&') { ch1 = char.ToLower(Value[num1 + 1], CultureInfo.InvariantCulture); string text1 = StringType.ToHalfwidthNumbers(Value.Substring(num1 + 2)); if (ch1 == 'h') { i64Value = Convert.ToInt64(text1, 0x10); } else if (ch1 == 'o') { i64Value = Convert.ToInt64(text1, 8); } else { throw new FormatException(); } return true; } if ((ch1 != ' ') && (ch1 != '\u3000')) { return false; } num1++; } return false; } //---------------------------------------------------- // DoubleType.TryParse(text1, ref num1); internal static bool TryParse(string Value, ref double Result) { bool flag1; CultureInfo info1 = Utils.GetCultureInfo(); NumberFormatInfo info3 = info1.NumberFormat; NumberFormatInfo info2 = DecimalType.GetNormalizedNumberFormat(info3); Value = StringType.ToHalfwidthNumbers(Value, info1); if (info3 == info2) { return double.TryParse(Value, NumberStyles.Any, info2, out Result); } try { Result = double.Parse(Value, NumberStyles.Any, info2); flag1 = true; } catch (FormatException) { flag1 = double.TryParse(Value, NumberStyles.Any, info3, out Result); } catch (Exception) { flag1 = false; } return flag1; }方案五： 直接引用vb運行庫(執行效率不高) 方法： 首先需要添加Visualbasic.runtime的引用 代碼中Using Microsoft.visualbasic; 程序中用Information.isnumeric("ddddd");