`必须在...处声明标量变量？有人可以解释这是什么吗？

Question

有人可以帮我宣布一个标量变量吗？我真的不明白这个Scalar Variable宣言.

下面是导致我的异常的代码.

int customer_Id;
int.TryParse(customer_IDTextBox1.Text, out customer_Id);

string SQL = @"UPDATE Customer
               SET Customer_Name = @customer_Name
               WHERE Customer_ID = @customer_Id";
SqlCommand sqlCommand = new SqlCommand(SQL, sqlConnection);
sqlCommand.Parameters.AddWithValue("@customer_Name", customer_Name);

sqlConnection.Open();
sqlCommand.ExecuteNonQuery();

Answer 1

您只将@customer_Name变量声明为参数.
添加行

sqlCommand.Parameters.AddWithValue("@customer_Id", customer_Id);

在你当前的AddWithValue路线下.