Add db.Ado.IsValidConnection()

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

@@ -73,6 +73,20 @@ namespace SqlSugar
         #endregion
 
         #region Connection
+        public virtual bool IsValidConnection() 
+        {
+            try
+            {
+                using (OpenAlways()) 
+                {
+                    return true;
+                }
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
         public virtual void Open()
         {
             CheckConnection();

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

@@ -164,6 +164,7 @@ namespace SqlSugar
         void Close();
         void Open();
         SugarConnection OpenAlways();
+        bool IsValidConnection();
         void CheckConnection();
 
         void BeginTran();