1 案一：Try...Catch(执行效率不高)
  2 private bool IsNumberic(string oText)
  3 {
  4           try
  5          {
  6                   int var1=Convert.ToInt32 (oText);
  7                   return true;
  8          }
  9           catch
 10          {
 11                   return false;
 12          }
 13 }
 14 
 15 方案二：正则表达式(推荐)
 16 a)
 17 public static bool IsNumeric(string value)
 18 {
 19          return Regex.IsMatch(value, @"^[+-]?\d*[.]?\d*$");
 20 }
 21 public static bool IsInt(string value)
 22 {
 23          return Regex.IsMatch(value, @"^[+-]?\d*$");
 24 }
 25 public static bool IsUnsign(string value)
 26 {
 27          return Regex.IsMatch(value, @"^\d*[.]?\d*$");
 28 }
 29  public static bool isTel(string strInput)
 30 {
 31         return Regex.IsMatch(strInput, @"\d{3}-\d{8}|\d{4}-\d{7}");
 32 }
 33 b)
 34 using System;
 35 using System.Text.RegularExpressions;
 36 public bool IsNumber(String strNumber)
 37 {
 38            Regex objNotNumberPattern=new Regex("[^0-9.-]");
 39            Regex objTwoDotPattern=new Regex("[0-9]*[.][0-9]*[.][0-9]*");
 40            Regex objTwoMinusPattern=new Regex("[0-9]*[-][0-9]*[-][0-9]*");
 41            String strValidRealPattern="^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$";
 42            String strValidIntegerPattern="^([-]|[0-9])[0-9]*$";
 43            Regex objNumberPattern =new Regex("(" + strValidRealPattern +")|(" + strValidIntegerPattern + ")");
 44            return !objNotNumberPattern.IsMatch(strNumber) &&
 45                   !objTwoDotPattern.IsMatch(strNumber) &&
 46                   !objTwoMinusPattern.IsMatch(strNumber) &&
 47                   objNumberPattern.IsMatch(strNumber);
 48 }
 49 
 50 
 51 方案三：遍历
 52 a)
 53 public bool isnumeric(string str)
 54 {
 55     char[] ch=new char[str.Length];
 56     ch=str.ToCharArray();
 57     for(int i=0;i    {
 58         if(ch[i]<48 || ch[i]>57)
 59             return false;
 60     }
 61     return true;
 62 }
 63 
 64 b)
 65 public bool IsInteger(string strIn) {
 66         bool bolResult=true;
 67         if(strIn=="") {
 68                bolResult=false;
 69         }
 70         else {
 71               foreach(char Char in strIn) {
 72                          if(char.IsNumber(Char))
 73                                 continue;
 74                          else {
 75                                  bolResult=false;
 76                                  break;
 77                          }
 78               }
 79         }
 80         return bolResult;
 81 }
 82 c)
 83 
 84 public static bool isNumeric(string inString)
 85 {
 86         inString=inString.Trim();
 87         bool haveNumber=false;
 88         bool haveDot=false;
 89         for(int i=0;i        {
 90                if (Char.IsNumber(inString[i]))
 91                 {
 92                         haveNumber=true;
 93                 }
 94                 else if(inString[i]=='.')
 95                 {
 96                         if (haveDot)
 97                         {
 98                                 return false;
 99                          }
100                          else
101                          {
102                                 haveDot=true;
103                           }
104                 }
105                 else if(i==0)
106                 {
107                           if(inString[i]!='+'&&inString[i]!='-')
108                           {
109                                   return false;
110                           }
111                 }
112                 else
113                 {
114                           return false;
115                  }
116                 if(i>20)
117                 {
118                           return false;
119                  }
120          }
121          return haveNumber;
122        }
123 
124 
125 方案四：改写vb的IsNumeric源代码(执行效率不高)
126 //主调函数
127 public static bool IsNumeric(object Expression)
128 {
129       bool flag1;
130       IConvertible convertible1 = null;
131       if (Expression is IConvertible)
132       {
133             convertible1 = (IConvertible) Expression;
134       }
135       if (convertible1 == null)
136       {
137             if (Expression is char[])
138             {
139                   Expression = new string((char[]) Expression);
140             }
141             else
142             {
143                   return false;
144             }
145       }
146       TypeCode code1 = convertible1.GetTypeCode();
147       if ((code1 != TypeCode.String) && (code1 != TypeCode.Char))
148       {
149             return Utils.IsNumericTypeCode(code1);
150       }
151       string text1 = convertible1.ToString(null);
152       try
153       {
154             long num2;
155             if (!StringType.IsHexOrOctValue(text1, ref num2))
156             {
157                   double num1;
158                   return DoubleType.TryParse(text1, ref num1);
159             }
160             flag1 = true;
161       }
162       catch (Exception)
163       {
164             flag1 = false;
165       }
166       return flag1;
167 }//子函数
168 // return Utils.IsNumericTypeCode(code1);
169 internal static bool IsNumericTypeCode(TypeCode TypCode)
170 {
171       switch (TypCode)
172       {
173             case TypeCode.Boolean:
174             case TypeCode.Byte:
175             case TypeCode.Int16:
176             case TypeCode.Int32:
177             case TypeCode.Int64:
178             case TypeCode.Single:
179             case TypeCode.Double:
180             case TypeCode.Decimal:
181             {
182                   return true;
183             }
184             case TypeCode.Char:
185             case TypeCode.SByte:
186             case TypeCode.UInt16:
187             case TypeCode.UInt32:
188             case TypeCode.UInt64:
189             {
190                   break;
191             }
192       }
193       return false;
194 }
195 
196 //-----------------
197 //StringType.IsHexOrOctValue(text1, ref num2))
198 internal static bool IsHexOrOctValue(string Value, ref long i64Value)
199 {
200       int num1;
201       int num2 = Value.Length;
202       while (num1 < num2)
203       {
204             char ch1 = Value[num1];
205             if (ch1 == '&')
206             {
207                   ch1 = char.ToLower(Value[num1 + 1], CultureInfo.InvariantCulture);
208                   string text1 = StringType.ToHalfwidthNumbers(Value.Substring(num1 + 2));
209                   if (ch1 == 'h')
210                   {
211                         i64Value = Convert.ToInt64(text1, 0x10);
212                   }
213                   else if (ch1 == 'o')
214                   {
215                         i64Value = Convert.ToInt64(text1, 8);
216                   }
217                   else
218                   {
219                         throw new FormatException();
220                   }
221                   return true;
222             }
223             if ((ch1 != ' ') && (ch1 != '\u3000'))
224             {
225                   return false;
226             }
227             num1++;
228       }
229       return false;
230 }
231 //----------------------------------------------------
232 // DoubleType.TryParse(text1, ref num1);
233 internal static bool TryParse(string Value, ref double Result)
234 {
235       bool flag1;
236       CultureInfo info1 = Utils.GetCultureInfo();
237       NumberFormatInfo info3 = info1.NumberFormat;
238       NumberFormatInfo info2 = DecimalType.GetNormalizedNumberFormat(info3);
239       Value = StringType.ToHalfwidthNumbers(Value, info1);
240       if (info3 == info2)
241       {
242             return double.TryParse(Value, NumberStyles.Any, info2, out Result);
243       }
244       try
245       {
246             Result = double.Parse(Value, NumberStyles.Any, info2);
247             flag1 = true;
248       }
249       catch (FormatException)
250       {
251             flag1 = double.TryParse(Value, NumberStyles.Any, info3, out Result);
252       }
253       catch (Exception)
254       {
255             flag1 = false;
256       }
257       return flag1;
258 }