Fix

Author: dariatiurina

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -5,6 +5,7 @@ Microsoft.AspNetCore.Components.ITempData.Keep() -> void
 Microsoft.AspNetCore.Components.ITempData.Keep(string! key) -> void
 Microsoft.AspNetCore.Components.ITempData.Peek(string! key) -> object?
 Microsoft.AspNetCore.Components.TempData
+Microsoft.AspNetCore.Components.TempData.ContainsValue(object? value) -> bool
 Microsoft.AspNetCore.Components.TempData.TempData() -> void
 Microsoft.AspNetCore.Components.TempData.Get(string! key) -> object?
 Microsoft.AspNetCore.Components.TempData.this[string! key].get -> object?

src/Components/Components/src/TempData.cs

@@ -64,6 +64,14 @@ public bool Remove(string key)
         return _data.Remove(key);
     }
 
+    /// <summary>
+    /// Returns true if the TempData dictionary contains the specified <paramref name="value"/>.
+    /// </summary>
+    public bool ContainsValue(object? value)
+    {
+        return _data.ContainsValue(value);
+    }
+
     /// <summary>
     /// Gets the data that should be saved for the next request.
     /// </summary>
@@ -153,14 +161,24 @@ IEnumerator IEnumerable.GetEnumerator()
 
     class TempDataEnumerator : IEnumerator<KeyValuePair<string, object?>>
     {
+        private readonly TempData _tempData;
         private readonly IEnumerator<KeyValuePair<string, object?>> _innerEnumerator;
 
         public TempDataEnumerator(TempData tempData)
         {
+            _tempData = tempData;
             _innerEnumerator = tempData._data.GetEnumerator();
         }
 
-        public KeyValuePair<string, object?> Current => _innerEnumerator.Current;
+        public KeyValuePair<string, object?> Current
+        {
+            get
+            {
+                var kvp = _innerEnumerator.Current;
+                _tempData.Remove(kvp.Key);
+                return kvp;
+            }
+        }
 
         object IEnumerator.Current => _innerEnumerator.Current;
 

src/Components/Components/test/TempDataTest.cs

@@ -158,7 +158,7 @@ public void Save_ReturnsOnlyRetainedKeys()
     public void Load_PopulatesDataFromDictionary()
     {
         var tempData = new TempData();
-        var dataToLoad = new Dictionary<string, object?>
+        var dataToLoad = new Dictionary<string, object>
         {
             ["Key1"] = "Value1",
             ["Key2"] = "Value2"
@@ -175,7 +175,7 @@ public void Load_ClearsExistingDataBeforeLoading()
     {
         var tempData = new TempData();
         tempData["ExistingKey"] = "ExistingValue";
-        var dataToLoad = new Dictionary<string, object?>
+        var dataToLoad = new Dictionary<string, object>
         {
             ["NewKey"] = "NewValue"
         };