Allow only one decimal point - CSharp System

CSharp examples for System:String Match

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Description

Allow only one decimal point

Demo Code


using System.Text;
using System.Globalization;
using System.Collections.Specialized;
using System.Collections;
using System;//from   ww w  .j  a v  a2  s. com

public class Main{
        /// <summary>
        /// Allow only one decimal point, used for IsNumericFloat.
        /// </summary>
        /// <param name="str">Input string to check</param>
        /// <param name="numberFormat">Used number format, e.g.
        /// CultureInfo.InvariantCulture.NumberFormat</param>
        /// <return>True if check succeeded, false otherwise</return>
        private static bool AllowOnlyOneDecimalPoint( string str,
            NumberFormatInfo numberFormat )
        {
            char[] strInChars = str.ToCharArray();
            bool hasGroupSeperator = false;
            int decimalSeperatorCount = 0;
            for ( int i = 0; i < strInChars.Length; i++ )
            {
                if ( numberFormat.CurrencyDecimalSeparator.IndexOf( strInChars[ i ] ) == 0 )
                {
                    decimalSeperatorCount++;
                } // if (numberFormat.CurrencyDecimalSeparator.IndexOf)

                // has float group seperators  ?
                if ( numberFormat.CurrencyGroupSeparator.IndexOf( strInChars[ i ] ) == 0 )
                {
                    hasGroupSeperator = true;
                } // if (numberFormat.CurrencyGroupSeparator.IndexOf)
            } // for (int)

            if ( hasGroupSeperator )
            {
                // If first digit is the group seperator or begins with 0,
                // there is something wrong, the group seperator is used as a comma.
                if ( str.StartsWith( numberFormat.CurrencyGroupSeparator ) ||
                    strInChars[ 0 ] == '0' )
                    return false;

                // look only at the digits in front of the decimal point
                string[] splittedByDecimalSeperator = str.Split(
                    numberFormat.CurrencyDecimalSeparator.ToCharArray() );

                #region Invert the digits for modulo check
                //   ==> 1.000 -> 000.1  ==> only after 3 digits 
                char[] firstSplittedInChars = splittedByDecimalSeperator[ 0 ].ToCharArray();
                int arrayLength = firstSplittedInChars.Length;
                char[] firstSplittedInCharsInverted = new char[ arrayLength ];
                for ( int i = 0; i < arrayLength; i++ )
                {
                    firstSplittedInCharsInverted[ i ] =
                        firstSplittedInChars[ arrayLength - 1 - i ];
                } // for (int)
                #endregion

                // group seperators are only allowed between 3 digits -> 1.000.000
                for ( int i = 0; i < arrayLength; i++ )
                {
                    if ( i % 3 != 0 && numberFormat.CurrencyGroupSeparator.IndexOf(
                        firstSplittedInCharsInverted[ i ] ) == 0 )
                    {
                        return false;
                    } // if (i)
                } // for (int)
            } // if (hasGroupSeperator)
            if ( decimalSeperatorCount > 1 )
                return false;

            return true;
        } // AllowOnlyOneDecimalPoint(str, numberFormat)
}

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