Add project input method with a folder dialog

CodeStatistics/CodeStatistics.csproj

@@ -52,7 +52,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="ConsoleUtil\ConsoleWrapper.cs" />
-    <Compile Include="Input\FileDialog.cs" />
+    <Compile Include="Input\MultiFolderDialog.cs" />
     <Compile Include="Input\IProjectInputMethod.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

CodeStatistics/Input/IProjectInputMethod.cs

@@ -0,0 +1,7 @@
+using CodeStatistics.ConsoleUtil;
+
+namespace CodeStatistics.Input{
+    interface IProjectInputMethod{
+        string[] Run(string[] args);
+    }
+}

CodeStatistics/Input/MultiFolderDialog.cs

@@ -0,0 +1,18 @@
+using System.Windows.Forms;
+
+namespace CodeStatistics.Input{
+    class MultiFolderDialog : IProjectInputMethod{
+        public string[] Run(string[] args){
+            OpenFileDialog dialog = new OpenFileDialog();
+            dialog.Filter = "Folders|\n";
+            dialog.CheckFileExists = false;
+            dialog.CheckPathExists = true;
+            dialog.DereferenceLinks = true;
+            dialog.AddExtension = false;
+            dialog.Multiselect = true;
+            dialog.AutoUpgradeEnabled = true;
+            dialog.ShowDialog();
+            return dialog.FileNames;
+        }
+    }
+}