C# StringExt 字符串扩展

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Service.Common
{
    public static class StringExt
    {
        public static string JoinToString<T>(this IEnumerable<T> collection, string split)
        {
            if (collection == null || !collection.Any()) return string.Empty;

StringBuilder sb = new StringBuilder();
            foreach (T t in collection)
            {
                sb.Append(t).Append(split);
            }
            if (sb.Length > 0)
            {
                sb.Remove(sb.Length - split.Length, split.Length);
            }

return sb.ToString();
        }

public static DateTime ToDateTime(this string value, DateTime defaultValue)
        {
            DateTime temp;
            if (DateTime.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static int ToInt32(this string value, int defaultValue)
        {
            int temp;
            if (int.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static long ToInt64(this string value, long defaultValue)
        {
            long temp;
            if (long.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static decimal ToDecimal(this string value, decimal defaultValue)
        {
            decimal temp;
            if (decimal.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static double ToDouble(this string value, double defaultValue)
        {
            double temp;
            if (double.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static float ToSingle(this string value, float defaultValue)
        {
            float temp;
            if (float.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return defaultValue;
            }
        }

public static DateTime? ToDateTimeNullable(this string value)
        {
            DateTime temp;
            if (DateTime.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static int? ToInt32Nullable(this string value)
        {
            int temp;
            if (int.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static long? ToInt64Nullable(this string value)
        {
            long temp;
            if (long.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static decimal? ToDecimalNullable(this string value)
        {
            decimal temp;
            if (decimal.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static double? ToDoubleNullable(this string value)
        {
            double temp;
            if (double.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static float? ToSingleNullable(this string value)
        {
            float temp;
            if (float.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return null;
            }
        }

public static T? Parse<T>(this string value, Func<string, T> parseFunc)
            where T : struct
        {
            if (string.IsNullOrEmpty(value))
            {
                return null;
            }
            else
            {
                return parseFunc(value.Trim());
            }
        }

public static int TryParseInt(this string value)
        {
            int temp;
            if (int.TryParse(value, out temp))
            {
                return temp;
            }
            else
            {
                return 0;
            }
        }

/// <summary>
        /// 类型转换
        /// </summary>
        public static T Value<T>(this object value)
        {
            if (value == null)
            {
                return default(T);
            }
            if (value is T)
                return (T)value;
            else if (value == DBNull.Value)
            {
                if (typeof(T) == typeof(DateTime))
                {
                    object o = new DateTime(1900, 1, 1);
                    return (T)o;
                }
                else
                    return default(T);
            }
            else if (value.ToString().ToLower() == "null")
                return default(T);            
            else
                return (T)Convert.ChangeType(value, typeof(T));
        }

public static T Value<T>(this object value, Func<object, T> funcConvert)
        {
            if (value == null)
            {
                return default(T);
            }

string s = value.ToString();
            if (string.IsNullOrEmpty(s) || s.ToLower() == "null")
            {
                return default(T);
            }

return funcConvert(value);
        }

public static object Value(this object value)
        {
            return Value<object>(value);
        }

public static string DecimalToString(this object value, string format)
        {
            if (value == null) return string.Empty;
            if (value is string)
            {
                if (value == string.Empty) return string.Empty;
                return Convert.ToDecimal(value).ToString(format);
            }
            else if (value is decimal)
            {
                return Convert.ToDecimal(value).ToString(format);
            }
            else
            {
                return value.ToString();
            }
        }

public static string ValueToString(this object value)
        {
            return ValueToString(value, false);
        }

public static string ValueToString(this object value, bool removeLines)
        {
            if (value == null)
            {
                return string.Empty;
            }

string s = value.ToString();
            if (string.IsNullOrEmpty(s) || s.ToLower() == "null")
            {
                return string.Empty;
            }

if (removeLines)
            {
                s = s.Replace("\r", " ").Replace("\n", " ").Replace("<br />", " ").Replace("<br/>", " ").Replace("<br>", " ").Replace("\t", " ");
            }

return s;
        }

public static object IsNull(this object value, object replaceValue)
        {
            if (value == null)
            {
                return replaceValue;
            }
            else
            {
                return value;
            }
        }

public static T IsNull<T>(this T value, T replaceValue)
        {
            if (value.Equals(default(T)))
            {
                return replaceValue;
            }
            else
            {
                return value;
            }
        }

public static string IsNull(this string value, string replaceValue)
        {
            if (string.IsNullOrEmpty(value))
            {
                return replaceValue;
            }
            else
            {
                return value;
            }
        }

/// <summary>
        /// 去除非法的文件字符
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string RemoveInvalidFileChars(this string input)
        {
            char[] invalidChars = Path.GetInvalidFileNameChars();
            foreach (char c in invalidChars)
            {
                input = input.Replace(c.ToString(), "");
            }
            return input;
        }

}
}