fix InvalidOperationException when items collection is empty

sbaeumlisberger · Jan 23, 2024 · eccd645 · eccd645
1 parent 53bed11
commit eccd645
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Showing 3 changed files with 12 additions and 3 deletions.
diff --git a/src/VirtualizingWrapPanel/VirtualizingWrapPanel.cs b/src/VirtualizingWrapPanel/VirtualizingWrapPanel.cs
@@ -439,7 +439,7 @@ private void FindStartIndexAndOffset()
 
             if (startOffsetY <= 0)
             {
-                startItemIndex = 0;
+                startItemIndex = Items.Count > 0 ? 0 : -1;
                 startItemOffsetX = 0;
                 startItemOffsetY = 0;
                 return;

diff --git a/src/VirtualizingWrapPanel/VirtualizingWrapPanel.csproj b/src/VirtualizingWrapPanel/VirtualizingWrapPanel.csproj
@@ -9,7 +9,7 @@
 
     <PropertyGroup>
         <title>VirtualizingWrapPanel</title>
-        <Version>2.0.3</Version>
+        <Version>2.0.4</Version>
         <Authors>S. Bäumlisbergerr</Authors>
         <Copyright>© S. Bäumlisberger</Copyright>
         <Description>Implementation of a VirtualizingWrapPanel for WPF.</Description>
@@ -36,7 +36,7 @@
         <PackageReadmeFile>README.md</PackageReadmeFile>
 
         <PackageReleaseNotes>
-- Fix: #51 VirtualizingWrapPanel does not shrink when items are changed
+- Fix: InvalidOperationException when items collection is empty
         </PackageReleaseNotes>
 
         <RootNamespace>WpfToolkit.Controls</RootNamespace>

diff --git a/src/VirtualizingWrapPanelTest/Tests/BasisTest.cs b/src/VirtualizingWrapPanelTest/Tests/BasisTest.cs
@@ -20,6 +20,15 @@ public class BasisTest
 {
     private VirtualizingWrapPanel vwp = TestUtil.CreateVirtualizingWrapPanel(500, 400);
 
+    [UIFact]
+    public void NoItems()
+    {
+        vwp = TestUtil.CreateVirtualizingWrapPanel(500, 400, itemCount: 0);
+
+        Assert.Equal(0, vwp.DesiredSize.Width);
+        Assert.Equal(0, vwp.DesiredSize.Height);
+    }
+
     [UIFact]
     public void Inital()
     {