C# 无法在表中插入标识列的显式值

代码：

在文本框中插入数据时，会发生以下错误：

当identity\u insert设置为OFF时，无法在表“Customers”中插入identity列的显式值

---

对于标识列，不能显式插入数据。要显式地将数据插入标识列，您需要将标识\u insert设置为ON。您可以使用以下命令来完成此操作

SET ANSI_NULLS OFF
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[AddUpdateCustomer]
      @CustomerID NCHAR(5),
      @ContactName NVARCHAR(30),
      @CompanyName NVARCHAR(40)
AS
BEGIN
      SET NOCOUNT ON;
    IF EXISTS(SELECT * FROM Customers WHERE CustomerID = @CustomerID)
    BEGIN
            UPDATE [Customers]
            SET [CompanyName] = @CompanyName
               ,[ContactName] = @ContactName
            WHERE CustomerID = @CustomerID
    END
    ELSE
    BEGIN
            INSERT INTO [Customers]
           ([CustomerID]
           ,[CompanyName]
           ,[ContactName])
        VALUES
           (@CustomerID
           ,@CompanyName
           ,@ContactName)
    END

    SELECT [CustomerID]
          ,[CompanyName]
          ,[ContactName]
      FROM Customers         
END

---

对于标识列，不能显式插入数据。要显式地将数据插入标识列，您需要将标识\u insert设置为ON。您可以使用以下命令来完成此操作

SET ANSI_NULLS OFF
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[AddUpdateCustomer]
      @CustomerID NCHAR(5),
      @ContactName NVARCHAR(30),
      @CompanyName NVARCHAR(40)
AS
BEGIN
      SET NOCOUNT ON;
    IF EXISTS(SELECT * FROM Customers WHERE CustomerID = @CustomerID)
    BEGIN
            UPDATE [Customers]
            SET [CompanyName] = @CompanyName
               ,[ContactName] = @ContactName
            WHERE CustomerID = @CustomerID
    END
    ELSE
    BEGIN
            INSERT INTO [Customers]
           ([CustomerID]
           ,[CompanyName]
           ,[ContactName])
        VALUES
           (@CustomerID
           ,@CompanyName
           ,@ContactName)
    END

    SELECT [CustomerID]
          ,[CompanyName]
          ,[ContactName]
      FROM Customers         
END

---

那么你的问题到底是什么？您可以将

IDENTITY\u INSERT

设置为ON，也可以不插入ID。如果CustomerID是标识列，则它不是nchar。你知道“身份”是什么意思吗？那么你的问题到底是什么？您可以将

IDENTITY\u INSERT

设置为ON，也可以不插入ID。如果CustomerID是标识列，则它不是nchar。你知道“身份”是什么意思吗？我不相信这是OP真正想要的，但你至少应该提到你应该在事后关掉它。我不相信这是OP真正想要的，但您至少应该提到，您应该在之后将其关闭。不要忘记检查客户端是否已刷新

CustomerID

。不要忘记检查客户端是否已刷新

CustomerID

ALTER PROCEDURE [dbo].[AddUpdateCustomer]
      @CustomerID  INT           OUTPUT,
      @ContactName NVARCHAR(30),
      @CompanyName NVARCHAR(40)
AS
BEGIN
      SET NOCOUNT ON;
    IF EXISTS(SELECT * FROM Customers WHERE CustomerID = @CustomerID)
    BEGIN
            UPDATE [Customers]
            SET [CompanyName] = @CompanyName
               ,[ContactName] = @ContactName
            WHERE CustomerID = @CustomerID
    END
    ELSE
    BEGIN
        INSERT INTO [Customers]
           ([CompanyName]
           ,[ContactName])
        VALUES
           (@CompanyName
           ,@ContactName)
        SET @CustomerID = SCOPE_IDENTITY()
    END

    SELECT [CustomerID]
          ,[CompanyName]
          ,[ContactName]
    FROM Customers  
    WHERE [CustomerID] = @CustomerID
END