FormatException occurs on SelectedIndexChanged of ListView

Question

This is the code:

private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            foreach (object item in listView1.SelectedItems)
            {
                string curItem = item.ToString();
                var parts = curItem.Split("{}XY=, ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                var xCoord = float.Parse(parts[0]);
                var yCoord = float.Parse(parts[1]);
                var point = new PointF(xCoord, yCoord);
                coordinates.Add(point);
                CloudEnteringAlert.pointtocolor = coordinates;
                pictureBox1.Invalidate();
            }
        }

When I used listBox1 SelectedIndexChanged event with the same code there were no problems. But now when I click and select item in the listView1, I am getting the exception on the line:

var xCoord = float.Parse(parts[0]);

Input string was not in a correct format.

System.FormatException was unhandled
  HResult=-2146233033
  Message=Input string was not in a correct format.
  Source=mscorlib
  StackTrace:
       at System.Number.ParseSingle(String value, NumberStyles options, NumberFormatInfo numfmt)
       at System.Single.Parse(String s)
       at Find_Distance.Form1.listView1_SelectedIndexChanged(Object sender, EventArgs e) in d:\C-Sharp\FindDistance\Find Distance\Find Distance\Form1.cs:line 382
       at System.Windows.Forms.ListView.OnSelectedIndexChanged(EventArgs e)
       at System.Windows.Forms.ListView.WmReflectNotify(Message& m)
       at System.Windows.Forms.ListView.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at System.Windows.Forms.Control.SendMessage(Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.Control.ReflectMessageInternal(IntPtr hWnd, Message& m)
       at System.Windows.Forms.Control.WmNotify(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
       at System.Windows.Forms.Control.DefWndProc(Message& m)
       at System.Windows.Forms.ListView.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.ListView.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at Find_Distance.Program.Main() in d:\C-Sharp\FindDistance\Find Distance\Find Distance\Program.cs:line 19
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

In this case, I clicked/selected the first item and I see that the variable item contains:

{ListViewItem: {281,145}}

Answer 1

Each item is a ListViewItem object, and the implementation of ListViewItem.ToString() is:

return "ListViewItem: {" + Text + "}";

And Text runs this snippet:

if (SubItemCount == 0)
    return string.Empty;
else
    return subItems[0].Text;

So you get "ListViewItem: {281,145}}", where "{281,145}" is the result of calling Text on the first sub item in the list.

---

I don't know exactly what you've inserted into your list, but assuming it's just a set of points entered as strings, you can try this instead:

foreach (object item in listView1.SelectedItems)
{
    string curItem = item.Text;
    var parts = curItem.Split(',');

    var xCoord = float.Parse(parts[0]);
    var yCoord = float.Parse(parts[1]);

    ...

And if there's any chance your list item might have non-numeric characters in it, consider using float.TryParse() instead. You can test the input value and if it's not a number, take some alternative action.