C#

Coder For Hire wrote:

I'm not trying to change the struct, I'm try to change the departmentId.

ECMA 334, §14.5.4 Member access:

... if E is a property or indexer access, then the value of the property or indexer access is obtained
(§14.1.1) and E is reclassified as a value.

ECMA 334, §18.3.3 Assignment:

When a property or indexer of a struct is the target of an assignment, the instance expression associated with
the property or indexer access shall be classified as a variable. If the instance expression is classified as a
value, a compile-time error occurs. This is described in further detail in §14.14.1.

public class Employee
    {
    private Department _TheDepartment;
    public Department TheDepartment
        {
        get { return _TheDepartment; }
        set { _TheDepartment = value; }
        }
    public Employee()
        {
        _TheDepartment.DepartmentId = 100;
        }
    }

public struct Department
    {
    public int DepartmentId { get; set; }
    }

namespace Sanebox2
{
    public class Employee
    {
        public Department TheDepartment { get; set; }

        public Employee(int departmentid = 100)
        {
            TheDepartment = new Department(departmentid);
        }
    }

    public struct Department
    {
        public int DepartmentId { get; set; }

        public Department(int id) : this()
        {
            DepartmentId = id;
        }
    }
}

// test somewhere in a method or event-handler, set break-point, examine 'e1, 'e2
// Employee e1 = new Employee();
// Employee e2 = new Employee(999);

TheDepartment = new Department { DepartmentId = departmentId };

• All fields in a struct have to be assigned by a constructor before the constructor can call a method in the struct.
• Setting a property counts as calling a method on the struct, which you can't do until all of the fields have been assigned.
• Since you're using an automatic property, you can't directly access the backing field to initialize it.
• Therefore, the only way to initialize the field is to call the default parameterless constructor first.

using (WebClient client = new WebClient())
{

    client.DownloadProgressChanged += (sender, e) =>
    {
        double bytesIn = double.Parse(e.BytesReceived.ToString());
        double totalBytes = double.Parse(e.TotalBytesToReceive.ToString());
        double percentage = bytesIn / totalBytes * 100;

        file.PercentDone = Math.Truncate(percentage);
    };

    client.DownloadFileCompleted += (sender, e) =>
    {
        Files.Remove(file);
    };

    await client.DownloadFileTaskAsync(new Uri(file.FileName), outputFile);
}

delegate void CloseDelegate();

void DoClose()
{
    if (this.InvokeRequired)
    {
        // if this is the background thread then invoke this
        // method on the main thread
        CloseDelegate d = new CloseDelegate(DoClose);
        this.Invoke(d);
    }
    else
    {
        // if it's the main thread ...
        // reduce the opacity gradually until the form disappears
        while (ms_frmSplash.Opacity > 0)
        {
            this.Opacity -= m_dblOpacityDecrement;
            System.Threading.Thread.Sleep(TIMER_INTERVAL);
        }
        this.Close(); // and close the form
    }
}

static public void CloseForm()
{
    if (ms_frmSplash != null && ms_frmSplash.IsDisposed == false)
    {
        ms_frmSplash.DoClose();
    }
    ms_oThread = null;  // we don't need these any more.
    ms_frmSplash = null;
}

static int TIMER_INTERVAL = 1 * 1000;  // 1 second sleep timer
double m_dblOpacityIncrement = .1;  // not used
double m_dblOpacityDecrement = .1;  // 10%

public partial class FormMain : Form
{
   public FormMain()
   {
      InitializeComponent();
   }

   ...
}