diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows/SwitchBuilder.cs b/dotnet/src/Microsoft.Agents.AI.Workflows/SwitchBuilder.cs
index c347ca84f3..286329b6ec 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows/SwitchBuilder.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows/SwitchBuilder.cs
@@ -37,13 +37,9 @@ public sealed class SwitchBuilder
 
         HashSet<int> indicies = [];
 
-        int executorIndex = 0;
-        foreach (ExecutorBinding? executor in executors)
+        foreach (ExecutorBinding executor in executors)
         {
-            if (executor is null)
-            {
-                throw new ArgumentNullException(nameof(executors), $"Executors collection contains a null element at index {executorIndex}.");
-            }
+            Throw.IfNull(executor, nameof(executors));
 
             if (!this._executorIndicies.TryGetValue(executor.Id, out int index))
             {
@@ -53,7 +49,6 @@ public sealed class SwitchBuilder
             }
 
             indicies.Add(index);
-            executorIndex++;
         }
 
         Func<object?, bool> casePredicate = WorkflowBuilder.CreateConditionFunc(predicate)!;
@@ -71,13 +66,9 @@ public sealed class SwitchBuilder
     {
         Throw.IfNull(executors);
 
-        int executorIndex = 0;
-        foreach (ExecutorBinding? executor in executors)
+        foreach (ExecutorBinding executor in executors)
         {
-            if (executor is null)
-            {
-                throw new ArgumentNullException(nameof(executors), $"Executors collection contains a null element at index {executorIndex}.");
-            }
+            Throw.IfNull(executor, nameof(executors));
 
             if (!this._executorIndicies.TryGetValue(executor.Id, out int index))
             {
@@ -87,7 +78,6 @@ public sealed class SwitchBuilder
             }
 
             this._defaultIndicies.Add(index);
-            executorIndex++;
         }
 
         return this;
diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
index e7f68e4f69..86699f4683 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
@@ -127,27 +127,15 @@ public static class WorkflowBuilderExtensions
     {
         Throw.IfNull(targets);
 
-        List<ExecutorBinding> targetList = [];
-        using IEnumerator<ExecutorBinding> targetEnumerator = targets.GetEnumerator();
-        if (!targetEnumerator.MoveNext())
+        List<ExecutorBinding> targetList = new();
+        foreach (ExecutorBinding target in targets)
         {
-            throw new ArgumentException("Targets collection cannot be empty.", nameof(targets));
-        }
-
-        int targetIndex = 0;
-        do
-        {
-            ExecutorBinding? target = targetEnumerator.Current;
-            if (target is null)
-            {
-                throw new ArgumentNullException(nameof(targets), $"Targets collection contains a null element at index {targetIndex}.");
-            }
+            Throw.IfNull(target, nameof(targets));
 
             targetList.Add(target);
-            targetIndex++;
         }
-        while (targetEnumerator.MoveNext());
 
+        Throw.IfNullOrEmpty(targetList, nameof(targets));
         return targetList;
     }