a

Extensions/BooleanExtension.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace ExtensionMethods
+{
+    public static class BooleanExtension
+    {
+        public static bool Turn(this bool obj)
+        {
+            return !obj;
+        }
+    }
+}

Extensions/DateTimeExtension.cs

@@ -16,5 +16,13 @@ namespace ExtensionMethods
         {
             return dateTime.ToString("yyyy-MM-dd");
         }
+
+        //public static string ToUnixTimeMilliseconds(this DateTimeOffset dateTimeOffset)
+        //{
+        //    // Unix时间戳是从1970年1月1日00:00:00 UTC开始的，所以我们需要减去这个时间  
+        //    TimeSpan timeSinceEpoch = dateTimeOffset - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);
+        //    // 将TimeSpan转换为毫秒  
+        //    return timeSinceEpoch.TotalMilliseconds.ToString();
+        //}
     }
 }

Extensions/ExtensionMethods.csproj

@@ -40,7 +40,9 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="BooleanExtension.cs" />
     <Compile Include="DateTimeExtension.cs" />
+    <Compile Include="ObjectExtension.cs" />
     <Compile Include="StringExtension.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>

Extensions/ObjectExtension.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace ExtensionMethods
+{
+    public static class ObjectExtension
+    {
+        public static string ToSafeTurnString(this object obj)
+        {
+            if (obj == null)
+                return string.Empty;
+
+            return obj.ToString();
+        }
+    }
+}

Extensions/StringExtension.cs

@@ -44,6 +44,18 @@ namespace ExtensionMethods
             return result;
         }
 
+        public static double ToDouble(this object obj)
+        {
+            if (obj == null)
+                return 0;
+            var str = obj.ToString().Trim();
+
+            double result;
+            double.TryParse(str, out result);
+
+            return result;
+        }
+
 
         public static decimal ToDecimal(this string obj)
         {
@@ -52,5 +64,13 @@ namespace ExtensionMethods
 
             return result;
         }
+
+
+        public static double ToDouble(this string obj)
+        {
+            double result;
+            double.TryParse(obj.Trim(), out result);
+            return result;
+        }
     }
 }