Adrian Johnson

If you try and make a change to a table in SQL Server 2008 Management Studio, such as the reordering of columns, or inserting a column in the middle of the table, you may see this message:

Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can’t be re-created or enabled the option Prevent saving changes that require the table to be re-created.

I’m not sure why it appears for this version of SQL Server, as I thought it was built on SQL Server 2005. Anyway, to get round it, perform the following:

1. In SQL Server 2008 Management Studio, click the Tools then Options menu options. 
2. Expand the list to show Designers, then Database and Table Designers.
3. Untick the checkbox for “Prevent saving changes that require table re-creation.”

One of the tasks that has been easy to implement in C# since 2005 has been the ability to drag and drop items into a treeview. I’ve been wanting to do the same for a WPF project, but there is a subtle difference.

For a WinForms application, you set the Effect property of the DragEventArgs object. For a WPF application, it’s now Effects (note the additional ‘s‘). So your drag enter code would become:

if (e.Data.GetDataPresent(DataFormats.Text))
{
  e.Effects = DragDropEffects.Copy;
}
else
{
  e.Effects = DragDropEffects.None;
}

Thanks to infoSupport for the heads up.

In C# WPF dialog results are different from Windows Forms. In Windows Forms you can set the value of the result in the button in the child form and retrieve it’s value in the parent. In WPF it’s different. Here’s how to do it:

1. In the Click function of the button on the child Window (the button you want to use to send the OK back to the parent), add:

DiaglogResult = true;

2.  In the code behind of the parent Window (e.g. in the function of a menu option which opens the child window) add:

 NewWindow newWindow = new NewWindow();

newWindow.ShowDialog();

if (newWindow.DialogResult.HasValue && newWindow.DialogResult.Value)

{

 // User clicked OK

}

else

{

// User clicked Cancel.

}

More details are on the MSDN web site.