From 0c7c073e82bf5bbf65929d71fa1c5cfb3e9f75c8 Mon Sep 17 00:00:00 2001
From: jinghongbo <jinghongbo@live.com>
Date: Fri, 11 Jun 2021 10:53:46 +0800
Subject: [PATCH] Update DamengUtils.cs
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当 value 等于null 时 string.Concat 返回 ""
---
 Providers/FreeSql.Provider.Dameng/DamengUtils.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Providers/FreeSql.Provider.Dameng/DamengUtils.cs b/Providers/FreeSql.Provider.Dameng/DamengUtils.cs
index cdf772064..930bb5c1f 100644
--- a/Providers/FreeSql.Provider.Dameng/DamengUtils.cs
+++ b/Providers/FreeSql.Provider.Dameng/DamengUtils.cs
@@ -56,7 +56,8 @@ public override DbParameter[] GetDbParamtersByObject(string sql, object obj) =>
                         case DmDbType.Char:
                         case DmDbType.VarChar:
                         case DmDbType.Text:
-                            value = string.Concat(value);
+                            if(value != null)
+                                value = string.Concat(value);
                             break;
                     }
                 }