Update for Sharepoint list containing lookup columns

Question

I have a SharePoint list containing 2 lookup columns (department and manager). How do I update values to SP list upon edit in gridview?

The following is the code for an update method :

public void updateRow(string itemID, string firstName, string lastName, string age, string eAddress, string department, string manager, string gender, string salary)
    {
        ClientContext clientContext = new ClientContext("https://xyz.xyz.com/sites/xyz/TrainingSite/");

        try
        {
            SP.List oList = clientContext.Web.Lists.GetByTitle("Employees");
            SP.CamlQuery camlQuery = new SP.CamlQuery();
            camlQuery.ViewXml = @"<Query><Where><Eq><FieldRef Name='ID' /><Value Type='Counter'>" + itemID + "</Value></Eq></Where></Query>";
            SP.ListItemCollection itemInfo = oList.GetItems(camlQuery);
            clientContext.Load(itemInfo);
            clientContext.ExecuteQuery();
            foreach (SP.ListItem item in itemInfo)
            {
                if (itemID == item["ID"].ToString())
                {
                    item["Title"] = firstName;
                    item["Last_x0020_Name"] = lastName;
                    item["u5ib"] = age;
                    item["Address"] = eAddress;

                    //Department column
                    //item["Department"] = department;
                    FieldLookupValue deptItem = new FieldLookupValue();
                    //deptItem.LookupId = Convert.ToInt32(TextBoxEditDepartment.SelectedValue); // here instead of 1, you should provide corresponding Department list item ID
                    item["Department"] = deptItem;
                    deptItem.LookupId = Convert.ToInt32(department);
                    item.Update();

                    //Manager column
                    //item["Manager"] = manager;
                    FieldLookupValue mgrItem = new FieldLookupValue();
                    item["Manager"] = mgrItem;
                    mgrItem.LookupId = Convert.ToInt32(manager);
                    item.Update();

                    item["Gender"] = gender;
                    item["Salary"] = salary;
                    item.Update();
                    break;
                }
            }
            clientContext.ExecuteQuery();
        }

Following is the code for RowUpdating event:

protected void gridview_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {

//Omitted few lines for clarity

        DropDownList department = (DropDownList)gridview.Rows[e.RowIndex].Cells[4].FindControl("ddlDepartment"); //department
        DropDownList manager = (DropDownList)gridview.Rows[e.RowIndex].Cells[5].FindControl("ddlManager"); //manager

//Omitted few lines for clarity            

        updateRow(itemID.Text, firstName.Text, lastName.Text, age.Text, eAddress.Text, department.Text, manager.Text, gender.Text, salary.Text); // call update method

        gridview.EditIndex = -1; //Turn the Grid to read only mode
        BindGrid(); // Rebind GridView to reflect changes made

        Response.Write("Update Seccessful!");
    }

I get an error like :"Input string was not in the correct format" for the following lines :

                    FieldLookupValue deptItem = new FieldLookupValue();
                    item["Department"] = deptItem;
                    deptItem.LookupId = Convert.ToInt32(department);
                    item.Update();

Please provide a solution :) Thanks!

Answer 1

You should interchange the lines in your code.

FieldLookupValue deptItem = new FieldLookupValue();
deptItem.LookupId = Convert.ToInt32(department);  //department should be department list item ID because its a lookup ID
item["Department"] = deptItem;
item.Update();

Hope this helps to you :)