Operation is not valid due to the current state of the object.

App Details:

Visual Studio 2010
Desktop Winforms App
MDI Child form with a Datagridview connected to SQL Server 2008

Error details:
When closing the form, debugger jumps to this line in form.designer.cs (one of the files you are not supposed to edit).

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
    if (disposing && (components != null))
    {
        components.Dispose();  //<<<---error points here
    }
    base.Dispose(disposing);
}

and here is the massive error...

System.InvalidOperationException was unhandled
  Message=Operation is not valid due to the current state of the object.
  Source=System.Windows.Forms
  StackTrace:
       at System.Windows.Forms.DataGridViewCell.GetInheritedStyle(DataGridViewCellStyle inheritedCellStyle, Int32 rowIndex, Boolean includeColors)
       at System.Windows.Forms.DataGridViewCell.GetPreferredWidth(Int32 rowIndex, Int32 height)
       at System.Windows.Forms.DataGridViewColumn.GetPreferredWidth(DataGridViewAutoSizeColumnMode autoSizeColumnMode, Boolean fixedHeight)
       at System.Windows.Forms.DataGridView.AutoResizeColumnInternal(Int32 columnIndex, DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal, Boolean fixedHeight)
       at System.Windows.Forms.DataGridView.OnColumnGlobalAutoSize(Int32 columnIndex)
       at System.Windows.Forms.DataGridView.OnColumnCommonChange(Int32 columnIndex)
       at System.Windows.Forms.DataGridViewCell.OnCommonChange()
       at System.Windows.Forms.DataGridViewComboBoxCell.set_DataSource(Object value)
       at System.Windows.Forms.DataGridViewComboBoxCell.DataSource_Disposed(Object sender, EventArgs e)
       at System.EventHandler.Invoke(Object sender, EventArgs e)
       at System.ComponentModel.Component.Dispose(Boolean disposing)
       at System.Windows.Forms.BindingSource.Dispose(Boolean disposing)
       at System.ComponentModel.Component.Dispose()
       at System.ComponentModel.Container.Dispose(Boolean disposing)
       at System.ComponentModel.Container.Dispose()
       at Onesource.MaterialReceiptsEntry.Dispose(Boolean disposing) in P:\Projects\myproject\sample\MaterialReceiptsEntry.Designer.cs:line 18
       at System.Windows.Forms.Form.WmClose(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.DefMDIChildProc(IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at System.Windows.Forms.Form.DefWndProc(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmSysCommand(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.DefMDIChildProc(IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at System.Windows.Forms.Form.DefWndProc(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmNcButtonDown(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.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 Onesource.Program.Main() in P:\Projects\myproject\sample\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.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

The solution:
I was looking through the ugly error stack above and found a lot of references to stuff like GetPreferredWidth. Having previously dealt with numerous problems involving AutoSizeColumnsMode and DataGridViewComboboxColumns,   I decided to try testing the form with AutoSizeColumnsMode set to None.  The layout did suck, but the form stopped crashing...

This means that the datagridview is trying to resize its columns during a form close!  Here is what I did to solve the problem.

I set the AutoSizeColumnsMode to AllCells and added a FormClose event as follows...




private void MaterialReceiptsEntry_FormClosing(object sender, FormClosingEventArgs e)

{

myDataGridView.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.None;

}

This ensures that the grid will not be updating its column sizes as the form is closing.

...

---

Bryan Valencia is a contributing editor and founder of Visual Studio Journey.  He owns and operates Software Services, a web design and hosting company in Manteca, California.

Case Schizophrenia and the DataGridViewComboboxColumn

So by default SQL Server (Microsoft) creates indices* and  does searches that are case insensitive.

Select * from orders where salesrep='bob' Will find BOB, bob, bOb, etc. (but not Robert)

So I have a DataGridViewComboboxColumn for that field, but since the data all comes from Paradox, where anything goes, I have a mixture of case scenarios.

As it turns out, even though your database cares not what capitalization you use, the combobox does.  It WILL NOT MATCH a field that has an alternate capitalization of whats in your data.

Example: if you have DONNA in the lookup list, and Donna in the orders table, the dropdown will display SOME RANDOM OTHER NAME.

It also throws a dataerror that looks like...

Order Entry [OrdersGrid]: Row 2 Column 16 Context Formatting, PreferredSize... System.Windows.Forms.DataGridViewDataErrorEventArgs DATA: TONYA 

...and it throws this error for each and every row you attempt to display on the screen.

The solution?

All I did was load the Purchase Orders table using the salesman as its own lookup.  like this

update Purchase_Order set Salesman=(select Salesman from Salesman S where S.Salesman=Purchase_Order.Salesman)

So, we're looking up the salesman, say "Bob" in the Salesman lookup table (finding, say "BOB") and writing that back over the Bob in the row, essentially updating the names in such a way as to match exactly what's in the lookup table.

Now our DataGridViewComboboxColumns work, and we didn't even have to edit the program!




...
* I still can't make myself use the word indexes.

---

Bryan Valencia is a contributing editor and founder of Visual Studio Journey.  He owns and operates Software Services, a web design and hosting company in Manteca, California.

I got this error message while trying to set up my on line site to use a different database from the default crap-tastic AspNetSqlProvider that takes 3 minutes to boot up with each web hit.
Here's the entire (incorrect) error message as IIS sends it.

Server Application Unavailable

The web application you are attempting to access on this web server is currently unavailable.  Please hit the "Refresh" button in your web browser to retry your request.
Administrator Note: An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur.

The first clue I got that something was Micro-softy was that there was no event logged in the event logger. I think I may have caused this problem when I logged in to the server with Remote Desktop and with Visual Web Developer at the same time, trying to make it select the correct database.

The Solution

1. go to the webserver (or remote-desktop in)
2. open IIS Manager (Microsoft Internet Information Services)
3. browse to the server and website that is broken
4. stop the website
5. open the site's properties page (right click the name of the site and pick "properties")
6. select the ASP.NET tab and change the .net version. Click Apply.
7. change the version back to the right (latest) version. Click Apply.
8. close the properties page and restart the website.

Error: Unrecognized attribute 'xmlns'. Note that attribute names are case sensitive

Visual Web Developer 2008 After publishing a newly created website to an existing server (after updating the .NET framework). I browse to the website from my workstation and get:

Error: Unrecognized attribute 'xmlns'. Note that attribute names are case sensitive

...in this file:

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\web.config

Here is what to do.

1. Edit the web.config file (get the filename from the bottom of the error message) . Make sure you're opening the version on the SERVER, not your local workstation.
2. find every occurrence of the text xmlns="", and DELETE it. Do NOT delete the line that has a long filename in the "" marks.
3. Save.
4. Go back to your workstation and refresh the browser.

After a long time, it refreshed for me. It was like the webserver had to re-initialize first. Then it started acting normally.