C# SQL Server 数据库错误

Question

我的代码出现以下错误:

An exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll but was not handled in user code

Additional information: The UPDATE statement conflicted with the FOREIGN KEY constraint

"FK_TutorID". The conflict occurred in database "NPTC", table "dbo.Tutor", column 'TutorID'.

这是我的代码:

// Instantiate a SqlConnection object with the COnnection String read.
SqlConnection conn = new SqlConnection(strConn.ToString());

// Instantiate a sqlcommand object, provide a update sql statement to add
// class to tutor record specified by a classID
SqlCommand cmd = new SqlCommand("
    UPDATE TuitionClass 
    SET TutorID = @tutorID 
    FROM TuitionClass 
    INNER JOIN Tutor ON TuitionClass.tutorID = Tutor.tutorID 
                     AND TuitionClassID = @selectedTuitionClassID", conn);

// Define the parameter used in SQL statement, value for the parameter is retrieved 
// from class's property
cmd.Parameters.AddWithValue("@tutorID", TutorID);
cmd.Parameters.AddWithValue("@selectedTuitionClassID", tuitionClassID);

// open a Database connection
conn.Open();

// Execute the SQL statement
int count = cmd.ExecuteNonQuery();

// Close database connection

我不确定哪里出了问题，因为我认为我的代码是正确的？

Answer 1

您在此处传递了无效的参数:

cmd.Parameters.AddWithValue("@tutorID", TutorID);

TutorID 与数据库中的Tutor 不匹配。