C# 4 and .NET 4

Moving, Copying, and Deleting files ❘ 781
enabled only when the example is actually displaying the properties of a file;
at all other times, they are disabled. The existing controls are also squashed
up a bit to stop the main form from getting too big. When the properties of
a selected file are displayed, FilePropertiesAndMovement automatically
places the full pathname of that file in the bottom text box for the user to
edit. Users can then click any of the buttons to perform the appropriate
operation. When they do, a message box is displayed that confirms the action
taken by the user (see Figure 29-5).
figure 29-5
When the user clicks the Yes button, the action is initiated. There are some
actions in the form that the user can take that will then cause the display to
be incorrect. For instance, if the user moves or deletes a file, you obviously cannot continue to display the
contents of that file in the same location. In addition, if you change the name of a file in the same folder,
your display will also be out of date. In these cases, FilePropertiesAndMovement resets its controls to
display only the folder where the file resides after the file operation.
looking at the Code for filePropertiesandmovement
To code this process, you need to add the relevant controls, as well as their event handlers, to the code
for the FileProperties sample. The new controls are given the names buttonDelete, buttonCopyTo,
buttonMoveTo, and textBoxNewPath.
First, look at the event handler that is called when the user clicks the Delete button:
protected void OnDeleteButtonClick(object sender, EventArgs e)
{
try
{
string filePath = Path.Combine(currentFolderPath,
textBoxFileName.Text);
string query = "Really delete the file\n" + filePath + y";
if (MessageBox.Show(query,
"Delete File", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
File.Delete(filePath);
DisplayFolderList(currentFolderPath);
}
}
catch(Exception ex)
{
MessageBox.Show("Unable to delete file. The following exception"
+ " occurred:\n" + ex.Message, "Failed");
}
}
code download FilePropertiesAndMovement.sln
The code for this method is contained in a try block because of the obvious risk of an exception being
thrown if, for example, you don’t have permission to delete the file, or the file is moved by another process
after it has been displayed but before the user presses the Delete button. You construct the path of the file to
be deleted from the CurrentParentPath field, which contains the path of the parent folder, and the text in
the textBoxFileName text box, which contains the name of the file.
The methods to move and copy the file are structured in a very similar manner:
protected void OnMoveButtonClick(object sender, EventArgs e)
{
try
{
string filePath = Path.Combine(currentFolderPath,
textBoxFileName.Text);
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