Need single control for save and opening a file in WPF

Question

Assuming there will be only one (.log) file

Say if user selects the path ex:(c:\test) and if the .log file exist then it should return c:\test\xyz.log.

if file not exist then in the same control user should specify the file name and it should be saved in the path in .log extension.

The below is the code :

string logFileName = string.Empty;

FolderBrowserDialog fbd = new FolderBrowserDialog();

if (fbd.ShowDialog() == System.Windows.Forms.DialogResult.OK)

logFileName = CheckLogFile(fbd.SelectedPath);

else

return;

if (!string.IsNullOrEmpty(logFileName))

LogFileName = Path.Combine(fbd.SelectedPath, logFileName);

else

{

Microsoft.Win32.SaveFileDialog sfd = new Microsoft.Win32.SaveFileDialog();

if (sfd.ShowDialog() == true)

{

LogFileName = sfd.FileName;

}

}

Any help?