What is the difference between Task.Result and await Task in C#?

Question

Accepted Answer

**.Result** — blocking. **await** — non-blocking.

**Task.Result:**
- Blocking call.
- Can cause deadlocks.
- Synchronously waits.

```csharp
Task<int> task = GetDataAsync();
int result = task.Result;  // Blocks thread!
```

**await:**
- Non-blocking.
- No deadlock.
- Asynchronously waits.

```csharp
int result = await GetDataAsync();  // Non-blocking
```

**Deadlock example:**
```csharp
// UI/ASP.NET context
private void Button_Click(object sender, RoutedEventArgs e) {
    // Bad — deadlock!
    var result = GetDataAsync().Result;

// Good — no deadlock
    var result = await GetDataAsync();
}
```

**Why Result causes deadlock:**
- Result blocks UI thread.
- Async method tries to resume on UI thread.
- Deadlock!

**Best practice:**
- Always use await.
- Avoid .Result and .Wait().

C#: What is the difference between Task.Result and await Task in C#?