take selected directory name to string using "FolderBrowserDialog&

im using "FolderBrowserDialog" for locate specific folder(maponline) and want to show message if user select different folder has different name,i dont have idea to take selected folder name to string,please help how to take that name, thank you ,

    FolderBrowserDialog folderBrowserDialog1 = new FolderBrowserDialog();
        if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
        {
            string foldername;//this name should Slelected folder name by FolderBrowserDialog
		    if(foldername =="maponline")
			{		 
            //action
            //copy data to startup path
            } 
			else
			{
			    messagebox.show("You should select specified folder",)
			}
                
        }