add sln picker

src/SharpIDE.Godot/Features/BottomPanel/BottomPanelManager.cs

@@ -45,6 +45,11 @@ public partial class BottomPanelManager : Panel
         GodotGlobalEvents.BottomPanelTabSelected += OnBottomPanelTabSelected;
     }
 
+    public override void _ExitTree()
+    {
+        GodotGlobalEvents.BottomPanelTabSelected -= OnBottomPanelTabSelected;
+    }
+
     private async Task OnBottomPanelTabSelected(BottomPanelType? type)
     {
         await this.InvokeAsync(() =>

src/SharpIDE.Godot/Features/SlnPicker/SlnPicker.cs

@@ -0,0 +1,26 @@
+using Godot;
+
+namespace SharpIDE.Godot.Features.SlnPicker;
+
+public partial class SlnPicker : Control
+{
+    private FileDialog _fileDialog = null!;
+
+    public override void _Ready()
+    {
+        _fileDialog = GetNode<FileDialog>("%FileDialog");
+    }
+    public async Task<string?> GetSelectedSolutionPath()
+    {
+        var tcs = new TaskCompletionSource<string?>(TaskCreationOptions.RunContinuationsAsynchronously);
+        await this.InvokeAsync(() =>
+        {
+            _fileDialog.FileSelected += path => tcs.SetResult(path);
+            _fileDialog.Canceled += () => tcs.SetResult(null);
+            _fileDialog.PopupCentered();
+        });
+        
+        var selectedPath = await tcs.Task;
+        return selectedPath;
+    }
+}

src/SharpIDE.Godot/Features/SlnPicker/SlnPicker.cs.uid

@@ -0,0 +1 @@
+uid://bjvwb6jg6jpsi

src/SharpIDE.Godot/Features/SlnPicker/SlnPicker.tscn

@@ -0,0 +1,21 @@
+[gd_scene load_steps=2 format=3 uid="uid://cwvhbsd1mdl2x"]
+
+[ext_resource type="Script" uid="uid://bjvwb6jg6jpsi" path="res://Features/SlnPicker/SlnPicker.cs" id="1_ciq0g"]
+
+[node name="SlnPicker" type="Control"]
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_ciq0g")
+
+[node name="FileDialog" type="FileDialog" parent="."]
+unique_name_in_owner = true
+oversampling_override = 1.0
+title = "Open a File"
+file_mode = 0
+access = 2
+filters = PackedStringArray("*.sln,*.slnx;Solution Files")
+use_native_dialog = true