SqlCommand返回值参数

也许看到这段代码的其他人将能够告诉我为什么returnID始终为0.我试图从插入的记录中检索新的ID。

public int AddToInventory(int PartID, int QtyOnHand, int SpokenFor, int LowOrderQty, int HighOrderQty, decimal LastBuyPrice, decimal AvgBuyPrice) { ConfigDAL config = new ConfigDAL(); string connstr = config.GetConnString(); SqlConnection conn = new SqlConnection(connstr); string query; query = "INSERT INTO Inventory (PartID, QtyOnHand, SpokenFor, LowOrderQty, HighOrderQty, LastBuyPrice, " + "AvgBuyPrice, CreatedOn, CreatedBy, ModifiedOn, ModifiedBy) " + "Values (@PartID, @QtyOnHand, @SpokenFor, @LowOrderQty, @HighOrderQty, @LastBuyPrice, @AvgBuyPrice, " + "@CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy)"; SqlCommand cmd = new SqlCommand(query, conn); cmd.CommandType = System.Data.CommandType.Text; cmd.Parameters.AddWithValue("@PartID", PartID); cmd.Parameters.AddWithValue("@QtyOnHand", QtyOnHand); cmd.Parameters.AddWithValue("@SpokenFor", SpokenFor); cmd.Parameters.AddWithValue("@LowOrderQty", LowOrderQty); cmd.Parameters.AddWithValue("@HighOrderQty", HighOrderQty); cmd.Parameters.AddWithValue("@LastBuyPrice", LastBuyPrice); cmd.Parameters.AddWithValue("@AvgBuyPrice", AvgBuyPrice); cmd.Parameters.AddWithValue("@CreatedOn", DateTime.Now); cmd.Parameters.AddWithValue("@CreatedBy", GlobalProp.UserName); cmd.Parameters.AddWithValue("@ModifiedOn", DateTime.Now); cmd.Parameters.AddWithValue("@ModifiedBy", GlobalProp.UserName); cmd.Parameters.Add("@ID", SqlDbType.Int).Direction = ParameterDirection.ReturnValue; conn.Open(); cmd.ExecuteNonQuery(); conn.Close(); int returnID = (int)cmd.Parameters["@ID"].Value; return returnID; } 

记录会很好地插入到表中，但返回值不正确。 我这样做了吗？

谢谢

Answer 1

您没有设置ID的位置，因此可以预期值会发生变化。 你必须这样做

  Select @ID = @Scope_Identity() -- If ID column is an Identity column 

要么

 Select @ID = @SomeGeneratedValue 

试试这个

 query = "INSERT INTO Inventory (PartID, QtyOnHand, SpokenFor, LowOrderQty, HighOrderQty, LastBuyPrice, " + "AvgBuyPrice, CreatedOn, CreatedBy, ModifiedOn, ModifiedBy) " + "Values (@PartID, @QtyOnHand, @SpokenFor, @LowOrderQty, @HighOrderQty, @LastBuyPrice, @AvgBuyPrice, " + "@CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy);" + " Declare @ID int;" + " Select @ID = Scope_Identity()"; 

Answer 2

在SQL查询中再添加一行：

选择@ID = scope_identity（）

Answer 3

根据我的经验， Direction ReturnValue不起作用。 它有道理，因为在像你这样的命令中，@ ID是一个脚本变量，因此它更像是一个输出参数而不是一个返回值。

对我来说，最好使用ParameterDirection.Output而不声明@ID（它是用.Output选项声明的）：

 cmd.Parameters.Add("@ID", SqlDbType.Int).Direction = ParameterDirection.Output; query = "INSERT INTO Inventory (PartID, QtyOnHand, SpokenFor, LowOrderQty, HighOrderQty, LastBuyPrice, " + "AvgBuyPrice, CreatedOn, CreatedBy, ModifiedOn, ModifiedBy) " + "Values (@PartID, @QtyOnHand, @SpokenFor, @LowOrderQty, @HighOrderQty, @LastBuyPrice, @AvgBuyPrice, " + "@CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy);" + " Set @ID = Scope_Identity()";