Adding new WinForms sample application (#452)

samples/CSharpWinForms/Form1.cs

@@ -0,0 +1,107 @@
+using System.Text;
+using Microsoft.Extensions.Logging;
+using Velopack;
+
+namespace CSharpWinForms;
+
+public partial class Form1 : Form
+{
+    private readonly UpdateManager _um;
+    private UpdateInfo? _update;
+
+    public Form1()
+    {
+        InitializeComponent();
+
+        string updateUrl = SampleHelper.GetReleasesDir(); // replace with your update url
+        _um = new UpdateManager(updateUrl, logger: Program.Log);
+
+        txtTextLog.Text = Program.Log.ToString();
+        Program.Log.LogUpdated += LogUpdated;
+        UpdateStatus();
+    }
+
+    private void LogUpdated(object? sender, LogUpdatedEventArgs e)
+    {
+        // logs can be sent from other threads
+        if (InvokeRequired) {
+            Invoke(() => LogUpdated(sender, e));
+            return;
+        }
+        txtTextLog.Text = e.Text;
+        txtTextLog.SelectionStart = txtTextLog.Text.Length;
+        txtTextLog.ScrollToCaret();
+    }
+
+    private void Progress(int percent)
+    {
+        // progress can be sent from other threads
+        if (InvokeRequired) {
+            Invoke(() => Progress(percent));
+            return;
+        }
+        lblStatus.Text = $"Downloading ({percent}%)...";
+    }
+
+    private void Working()
+    {
+        Program.Log.LogInformation("");
+        btnCheckUpdate.Enabled = false;
+        btnDownloadUpdate.Enabled = false;
+        btnRestartApply.Enabled = false;
+        lblStatus.Text = "Working...";
+    }
+
+    private void UpdateStatus()
+    {
+        StringBuilder sb = new StringBuilder();
+        sb.AppendLine($"Velopack version: {VelopackRuntimeInfo.VelopackNugetVersion}");
+        sb.AppendLine($"This app version: {(_um.IsInstalled ? _um.CurrentVersion : "(n/a - not installed)")}");
+
+        if (_update != null) {
+            sb.AppendLine($"Update available: {_update.TargetFullRelease.Version}");
+            btnDownloadUpdate.Enabled = true;
+        } else {
+            btnDownloadUpdate.Enabled = false;
+        }
+
+        if (_um.UpdatePendingRestart != null) {
+            sb.AppendLine("Update ready, pending restart to install");
+            btnRestartApply.Enabled = true;
+        } else {
+            btnRestartApply.Enabled = false;
+        }
+
+        lblStatus.Text = sb.ToString();
+        btnCheckUpdate.Enabled = true;
+    }
+
+    private async void btnCheckUpdate_Click(object sender, EventArgs e)
+    {
+        Working();
+        try {
+            // ConfigureAwait(true) so that UpdateStatus() is called on the UI thread
+            _update = await _um.CheckForUpdatesAsync().ConfigureAwait(true);
+        } catch (Exception ex) {
+            Program.Log.LogError(ex, "Error checking for updates");
+        }
+        UpdateStatus();
+    }
+
+    private async void btnDownloadUpdate_Click(object sender, EventArgs e)
+    {
+        Working();
+        try {
+            // ConfigureAwait(true) so that UpdateStatus() is called on the UI thread
+            await _um.DownloadUpdatesAsync(_update!, Progress).ConfigureAwait(true);
+        } catch (Exception ex) {
+            Program.Log.LogError(ex, "Error downloading updates");
+        }
+        UpdateStatus();
+    }
+
+    private void btnRestartApply_Click(object sender, EventArgs e)
+    {
+        _um.ApplyUpdatesAndRestart(_update!);
+    }
+}