Add db.Ado.OpenAlways()

Src/Asp.Net/SqlSugar/Abstract/AdoProvider/AdoProvider.cs

@@ -77,6 +77,11 @@ namespace SqlSugar
         {
             CheckConnection();
         }
+        public virtual void OpenAlways() 
+        {
+            this.Context.CurrentConnectionConfig.IsAutoCloseConnection = false;
+            this.Open();
+        }
         public virtual void Close()
         {
             if (this.Transaction != null)

Src/Asp.Net/SqlSugar/Interface/IAdo.cs

@@ -163,6 +163,7 @@ namespace SqlSugar
         void Dispose();
         void Close();
         void Open();
+        void OpenAlways();
         void CheckConnection();
 
         void BeginTran();