方案一：Try...Catch(執行效率不高)
/// <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)
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)
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：遍歷
a)
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)
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)
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)

//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");

?

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