数据源中String类型的给定值无法转换为指定目标列的int类型

Question

I am trying to read values from xml file and then use the bulkcopy to insert the data into my database.

I am using a custom class which is:

class Customer
    {
        public int CustomerID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int ShowsNumber { get; set; }
        public int VisitNumber { get; set; }
        public int Cancellation { get; set; }
    }

and I read the data like this:

List<Customer> customersList =
                (
                    from e in XDocument.Load(file).Root.Elements("cust")
                    select new Customer
                    {
                        CustomerID = (int)e.Attribute("custid"),
                        FirstName = (string)e.Attribute("fname"),
                        LastName = (string)e.Attribute("lname"),
                        ShowsNumber = (int)e.Attribute("count_noshow"),
                        VisitNumber = (int)e.Attribute("count_resos"),
                        Cancellation = (int)e.Attribute("count_cancel"),
                    }).ToList();

Then I insert that customersList to a datatabe like this:

DataTable dataTable = getBasicDataTable();
for (int i = 0; i < customersList.Count; i++)
                {
                    DataRow datarows = dataTable.NewRow();
                    datarows[0] = customersList[i].CustomerID;
                    datarows[1] = customersList[i].FirstName;
                    datarows[2] = customersList[i].LastName;
                    datarows[3] = customersList[i].ShowsNumber;
                    datarows[4] = customersList[i].VisitNumber;
                    datarows[5] = customersList[i].Cancellation;
                    dataTable.Rows.Add(datarows);
                }

then I insert the data to my database like this:

but I got this exception

using (SqlBulkCopy sbc = new SqlBulkCopy(GetConnectionString()))
            {
                sbc.DestinationTableName = XMLReader.databaseTable;
                sbc.WriteToServer(dataTable);
            }

The given value of type String from the data source cannot be converted to type int of the specified target column.

as you see, when I extract the data from my xml, I already use the cast to int and to string and it is working. so why when inserting to the database I got that exception?

Note

In order to give you the whole code, this is the getBasicDataTable fuction

private DataTable getBasicDataTable()
        {
            DataTable dataTable = new DataTable();
            dataTable.Clear();
            dataTable.Columns.Add("customerID");
            dataTable.Columns.Add("firstName");
            dataTable.Columns.Add("lastName");
            dataTable.Columns.Add("showsNumber");
            dataTable.Columns.Add("visitNumber");
            dataTable.Columns.Add("cancellation");
            return dataTable;
        }

Answer 1

You need to specify the column as integer while defining the datatable . Like this:-

dataTable.Columns.Add("customerID", typeof(int));

Edit:
The other reason i suspect is probably the way you are binding your datatable (I mean the order of columns) doesn't match with that of database table. Reason being I think default mapping is not Name to Name rather its Index to Index in SqlBulkCopy . So Kindly re-check your database table order, It should look like:-

CustomerID (INT)
FirstName (VARCHAR\NVARCHAR)
LastName (VARCHAR\NVARCHAR)
ShowsNumber (INT)
VisitNumber (INT)
Cancellation (INT)

Answer 2

As far as I am aware, you need to set the Type of the column on the datatable, otherwise it will presume string (because nearly everything can be converted as such).

Before you set the values, try:

dataTable.Columns[2].Type = typeof (int);

or, alternatively, you can specify it when defining the columns:

dataTable.Columns.Add("ShowsNumber", typeof(int));