Ensures a string starts with a specific string. - CSharp System

CSharp examples for System:String Start End

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Description

Ensures a string starts with a specific string.

Demo Code

//  Copyright ? 2011, Grid Protection Alliance.  All Rights Reserved.
using System.Text.RegularExpressions;
using System.Text;
using System.IO;//from  w  ww.  j a  va 2  s.  c om
using System.Globalization;
using System.ComponentModel;
using System.Collections.Generic;
using System;

public class Main{
        /// <summary>
        /// Ensures a string starts with a specific string.
        /// </summary>
        /// <param name="value">Input string to process.</param>
        /// <param name="startString">The string desired at string start.</param>
        /// <returns>The sent string with string at the start.</returns>
        public static string EnsureStart(this string value, string startString)
        {
            if (string.IsNullOrEmpty(value))
                return "";

            if (string.IsNullOrEmpty(startString))
                return value;

            if (value.IndexOf(startString) == 0)
                return value;
            else
                return string.Concat(startString, value);
        }
        /// <summary>
        /// Ensures a string starts with a specific character.
        /// </summary>
        /// <param name="value">Input string to process.</param>
        /// <param name="startChar">The character desired at string start.</param>
        /// <param name="removeRepeatingChar">Set to <c>true</c> to ensure one and only one instance of <paramref name="startChar"/>.</param>
        /// <returns>The sent string with character at the start.</returns>
        public static string EnsureStart(this string value, char startChar, bool removeRepeatingChar)
        {
            if (string.IsNullOrEmpty(value))
                return "";

            if (startChar == 0)
                return value;

            if (value[0] == startChar)
            {
                if (removeRepeatingChar)
                    return value.Substring(LastIndexOfRepeatedChar(value, startChar, 0));
                return value;
            }
            else
                return string.Concat(startChar, value);
        }
        /// <summary>
        /// Ensures a string starts with a specific character.
        /// </summary>
        /// <param name="value">Input string to process.</param>
        /// <param name="startChar">The character desired at string start.</param>
        /// <returns>The sent string with character at the start.</returns>
        public static string EnsureStart(this string value, char startChar)
        {
            return EnsureStart(value, startChar, false);
        }
}

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