Add FolderPicker to source selection in config menu.

ConfForm.cs

@@ -44,14 +44,16 @@ namespace PDF_Merge
             if (sourceBox.Text.Length > 0)
             {
                 appSettings.Settings["PDF-Path"].Value = sourceBox.Text;
-            } else
+            }
+            else
             {
                 MessageBox.Show("Source path cannot be empty.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
             }
             if (outputBox.Text.Length > 0)
             {
                 appSettings.Settings["PDF-Output"].Value = outputBox.Text;
-            } else
+            }
+            else
             {
                 MessageBox.Show("Output path cannot be empty.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
             }
@@ -60,5 +62,17 @@ namespace PDF_Merge
             ConfigurationManager.RefreshSection("appSettings");
             this.Close();
         }
+
+        private void sourceDirBtn_Click(object sender, EventArgs e)
+        {
+            using (var SourceDirPicker = new FolderBrowserDialog())
+            {
+                if(SourceDirPicker.ShowDialog() == DialogResult.OK)
+                {
+                    var sourceDir = SourceDirPicker.SelectedPath;
+                    sourceBox.Text = sourceDir;
+                }
+            }
+        }
     }
 }