[AI Projects] Improve error message when no connection is found (#48767)

Author: ShivangiReja

sdk/ai/Azure.AI.Projects/src/Custom/Connection/ConnectionsClient.cs

@@ -543,7 +543,7 @@ public virtual Response<ConnectionResponse> GetDefaultConnection(ConnectionType
 
             if (connections?.Value == null || connections.Value.Count == 0)
             {
-                throw new InvalidOperationException("No connections found for the specified parameters.");
+                throw new InvalidOperationException($"No connections found for '{category}'. At least one connection is required. Please add a new connection in the Azure AI Foundry portal by following the instructions here: https://aka.ms/azsdk/azure-ai-projects/how-to/connections-add");
             }
 
             ConnectionResponse connection = connections.Value[0];

sdk/ai/Azure.AI.Projects/tests/Samples/Extensions/Sample_AIInference.cs

@@ -57,4 +57,22 @@ public void InferenceEmbedding()
             Console.WriteLine($"Index: {item.Index}, Embedding: <{string.Join(", ", embedding)}>");
         }
     }
+
+    [Test]
+    public void ThrowsWhenNoConnection()
+    {
+        var connectionString = TestEnvironment.AzureAICONNECTIONSTRING;
+        var modelDeploymentName = TestEnvironment.MODELDEPLOYMENTNAME;
+        AIProjectClient client = new AIProjectClient(connectionString);
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+        {
+            ChatCompletionsClient chatClient = client.GetChatCompletionsClient();
+        });
+
+        Assert.AreEqual(
+            $"No connections found for '{ConnectionType.Serverless}'. At least one connection is required. Please add a new connection in the Azure AI Foundry portal by following the instructions here: https://aka.ms/azsdk/azure-ai-projects/how-to/connections-add",
+            ex.Message);
+        Console.WriteLine(ex.Message);
+    }
 }

sdk/ai/Azure.AI.Projects/tests/Samples/Extensions/Sample_AzureOpenAI.cs

@@ -23,4 +23,22 @@ public void AzureOpenAIChatCompletion()
         ChatCompletion result = chatClient.CompleteChat("List all the rainbow colors");
         Console.WriteLine(result.Content[0].Text);
     }
+
+    [Test]
+    public void ThrowsWhenNoConnection()
+    {
+        var connectionString = TestEnvironment.AzureAICONNECTIONSTRING;
+        var modelDeploymentName = TestEnvironment.MODELDEPLOYMENTNAME;
+        AIProjectClient client = new AIProjectClient(connectionString);
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+        {
+            ChatClient chatClient = client.GetAzureOpenAIChatClient("gpt-4o-mini");
+        });
+
+        Assert.AreEqual(
+            $"No connections found for '{ConnectionType.AzureOpenAI}'. At least one connection is required. Please add a new connection in the Azure AI Foundry portal by following the instructions here: https://aka.ms/azsdk/azure-ai-projects/how-to/connections-add",
+            ex.Message);
+        Console.WriteLine(ex.Message);
+    }
 }

sdk/ai/Azure.AI.Projects/tests/Samples/Extensions/Sample_Search.cs

@@ -29,4 +29,22 @@ public void Search()
             Console.WriteLine($"{id}: {name}");
         }
     }
+
+    [Test]
+    public void ThrowsWhenNoConnection()
+    {
+        var connectionString = TestEnvironment.AzureAICONNECTIONSTRING;
+        var modelDeploymentName = TestEnvironment.MODELDEPLOYMENTNAME;
+        AIProjectClient client = new AIProjectClient(connectionString);
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+        {
+            SearchClient searchClient = client.GetSearchClient("index");
+        });
+
+        Assert.AreEqual(
+            $"No connections found for '{ConnectionType.AzureAISearch}'. At least one connection is required. Please add a new connection in the Azure AI Foundry portal by following the instructions here: https://aka.ms/azsdk/azure-ai-projects/how-to/connections-add",
+            ex.Message);
+        Console.WriteLine(ex.Message);
+    }
 }