使用foreach访问列表

Question

I am using a foreach loop to access the values of objects(of type Meal) stored in a list. Then I am calling a database query to save these values into the database .

This is the code I'm using :

foreach (Meal ml in mVals)
            {
                    mID = ml.mealID;
                    MessageBox.Show(Convert.ToString(mID));
                    string oString2 = " INSERT into [dbo].[OrderMeal] (orderId,mealId,quantity) " + " VALUES ('" + orderId + "','" + mID + "','" + Convert.ToInt32(quant.Text) + "') ;";
                    SqlCommand oCmd2 = new SqlCommand(oString2, myConnection);
                    oCmd2.ExecuteNonQuery();

            }

However, this only works for the last value in the list. The next loop iteration seems to be doing the same function, thereby saving the same record, giving an

error of violating the primary key constraint .

Is there some error in the way I am looping through the List?

Answer 1

What the structure of OrderMeal table? Probably you have primary key in your table, and you need to vetify that you don't duplicate him.

try to enter the value in the list from the sql management. verify that you don't have special characters in each item in the list( like comma and Apostrophe).

I think you can concatenate a set of insert statement and then ExcuteNonQuery for better performance.