通过LINQ在不同的数据库中更新

Question

我有一个如下所示的数据库：

第一：

CommissionsV2（表 = Entity_Product_Point）
这也是我的 DBML，它只有一张表。

第二：

WebEnroll（表 = PlanMaster）
这是我的另一个 DBML，其中有一个表。

现在，通过 LINQ，我在其中添加一行，其中包含如下查询：

                        CommissionsV2DataContext cv = new CommissionsV2DataContext();
                        Entity_Product_Point ev = new Entity_Product_Point();
                        ev.Entity_ID = getEntity;
                        ev.Product_ID = tr.First();
                        ev.HiCommissionOld = (double)firststYrComp;
                        ev.LowCommissionOld = (double)recurringComp;
                        ev.HiCommission = (double)finalFirstYrComp * 100;
                        ev.LowCommission = (double)finalRecurringComp * 100;
                        ev.DateCreated = System.DateTime.Now;

                        cv.Entity_Product_Points.InsertOnSubmit(ev);
                        cv.SubmitChanges();

现在我的更新语句如下所示：

 protected void gvShowComm_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {

        //Getting the Entity_ID from the Session!
        int getEntity = Int16.Parse(Session["EntitySelected"].ToString());

        //Accessing the variables from the controls!
        System.Web.UI.WebControls.TextBox product_ID = gvShowComm.Rows[e.RowIndex].FindControl("ProductName") as System.Web.UI.WebControls.TextBox;
        System.Web.UI.WebControls.TextBox planName = gvShowComm.Rows[e.RowIndex].FindControl("PlanName") as System.Web.UI.WebControls.TextBox;
        System.Web.UI.WebControls.TextBox hiCommOld = gvShowComm.Rows[e.RowIndex].FindControl("HiComm") as System.Web.UI.WebControls.TextBox;
        System.Web.UI.WebControls.TextBox lowCommOld = gvShowComm.Rows[e.RowIndex].FindControl("LowComm") as System.Web.UI.WebControls.TextBox;

        //Storing the values into variables!
        int product = Int16.Parse(product_ID.Text);
        string plan = planName.Text;
        int hiOld = Int16.Parse(hiCommOld.Text);
        int lowOld = Int16.Parse(lowCommOld.Text);

        //Updating the values into the table through LINQ!
        dbWebEnrollDataContext dt = new dbWebEnrollDataContext(); //This has PlanName in PlanMaster Table.
        CommissionsV2DataContext cv = new CommissionsV2DataContext(); //Entity_Product_Point has all the other columns which needs to be updated!

        Entity_Product_Point ev = cv.Entity_Product_Points.Single(c => c.Product_ID == product);
        ev.HiCommissionOld = hiOld;
        ev.LowCommissionOld = lowOld;
        ev.Entity_ID = getEntity;
        cv.SubmitChanges();

Answer 1

为了更新，您需要检索需要更新的实体。

所以在你的情况下它将是：

Entity_Product_Point ev = cv.Entity_Product_Points.Single(c => c.Product_ID == product);
ev.HiCommissionOld = hiOld;
ev.LowCommissionOld = lowOld;
// Retrieve the plan that needs to be updated and set the name
// Submit the changes
cv.SubmitChanges();
// Retrieve the new values and rebind the gridview against the new values