CODEWITHSUNDEEP
c#winforms
user1417068
user1417068

Reputation: 82

Unable to cast object of type ,Drawing Item

How to fix problem follow :

when I drawItem, then get message error: "Unable to cast object of type 'System.Collections.Generic.List`1[mypro.InfoDialog+Mycontact]' to type 'Mycontact'."

C# code at line number:

public class Mycontact
{
        public string P_DISPLAY_NAME    { get; set; }
        public string P_AVAILABILITY    { get; set; }
        public string P_AVATAR_IMAGE    { get; set; }
}

Mycontact fbContact;

private void AddDataToList()
{
    var fbList = new List<Mycontact>();
    foreach (dynamic item in result.data)
    {
        fbContact = new Mycontact() { P_DISPLAY_NAME = (string)item["name"], P_AVAILABILITY = (string)item["online_presence"]};
        fbList.Add(fbContact);
        listBox1.Items.Add(fbList);
    }
}


private int mouseIndex = -1;


private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{

    if (e.Index == -1) return;

    line number:
    Mycontact contact = (Mycontact)listBox1.Items[e.Index];

    Brush textBrush = SystemBrushes.WindowText;
        if (e.Index > -1)
        {
            // Drawing the frame
            if (e.Index == mouseIndex)
            {
                e.Graphics.FillRectangle(SystemBrushes.HotTrack, e.Bounds);
                textBrush = SystemBrushes.HighlightText;
            }
            else
            {
                if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
                {
                    e.Graphics.FillRectangle(SystemBrushes.Highlight, e.Bounds);
                    textBrush = SystemBrushes.HighlightText;
                }else{
                    e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
                }
                // Drawing the text
                e.Graphics.DrawString(contact.P_DISPLAY_NAME, e.Font, textBrush,    e.Bounds.Left + 20, e.Bounds.Top);
            }
        }
}

Upvotes: 0

Views: 355

Answers (2)

Raf
Raf

Reputation: 683

You are adding the full list to the listbox as a single item:

listBox1.Items.Add(fbList);

So the line

(Mycontact)listBox1.Items[e.Index];

Returns a list of MyContact objects instead of a single MyContact object.

So to fix it you could just add contact per contact to the list like this

listBox1.Items.Add(fbContact);

Upvotes: 1

Me.Name
Me.Name

Reputation: 12544

It seems the whole listed is added to listbox1 instead of a single item (listBox1.Items.Add(fbList))

Shouldn't it be:

listBox1.Items.Add(fbContact);

Alternatively, you could set listBox1.DataSource = fbList after the loop

Upvotes: 4

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