C#判断一个string是否可以为数字的几种解决方案

  方案一:Try...Catch(执行效率不高)view plaincopy to clipboardprint?
  /// <summary>
  /// 名称:IsNumberic
  /// 功能:判断输入的是否是数字
  /// 参数: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>
  /// 名称:IsNumberic
  /// 功能:判断输入的是否是数字
  /// 参数: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:正则表达式(推荐)
  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:遍历 www.devdao.com
  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:改写vb的IsNumeric源代码(执行效率不高)view plaincopy to clipboardprint?
  //主调函数
  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;
  }
  
  //子函数
  // 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;
  }
  //主调函数
  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;
  }
  //子函数
  // 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运行库(执行效率不高)
  方法: 首先需要添加Visualbasic.runtime的引用
  代码中Using Microsoft.visualbasic;
  程序中用Information.isnumeric("ddddd");