添加项目文件。

Extensions/StringExtension.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+
+namespace ExtensionMethods
+{
+    public static class StringExtension
+    {
+        /// <summary>
+        /// 四舍五入保留2位小数
+        /// </summary>
+        /// <param name="obj"></param>
+        /// <returns></returns>
+        public static decimal ToDecimalR(this string obj)
+        {
+            return Math.Round(obj.ToDecimal(), 2, MidpointRounding.AwayFromZero);
+        }
+
+        /// <summary>
+        /// 四舍五入保留2位小数
+        /// </summary>
+        /// <param name="obj"></param>
+        /// <returns></returns>
+        public static decimal ToDecimalR(this object obj)
+        {
+            return Math.Round(obj.ToDecimal(), 2, MidpointRounding.AwayFromZero);
+        }
+        public static decimal ToDecimalR(this decimal obj)
+        {
+            return Math.Round(obj, 2, MidpointRounding.AwayFromZero);
+        }
+
+        public static decimal ToDecimal(this object obj)
+        {
+            if (obj == null)
+                return 0;
+            var str = obj.ToString().Trim();
+
+            decimal result;
+            decimal.TryParse(str, out result);
+
+            return result;
+        }
+
+
+        public static decimal ToDecimal(this string obj)
+        {
+            decimal result;
+            decimal.TryParse(obj.Trim(), out result);
+
+            return result;
+        }
+    }
+}