# AddFieldFromExpressionAsync Method

## Overloads

| [AddFieldFromExpressionAsync(String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm#Qlik_Engine_App_AddFieldFromExpressionAsync_System_String_System_String_) |  | Adds a field on the fly. |
| --- | --- | --- |
| [AddFieldFromExpressionAsync(AsyncHandle, String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm#Qlik_Engine_App_AddFieldFromExpressionAsync_Qlik_Engine_AsyncHandle_System_String_System_String_) |  | Adds a field on the fly. |
| [AddFieldFromExpressionAsync<T>(AsyncHandle, Func<Response, T>, String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm#Qlik_Engine_App_AddFieldFromExpressionAsync__1_Qlik_Engine_AsyncHandle_System_Func_Qlik_Engine_Communication_IO_Response___0__System_String_System_String_) |  | Adds a field on the fly. |

[](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm) [](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm)

## AddFieldFromExpressionAsync(String, String)

Adds a field on the fly.

### Declaration

```

          public Task<bool> AddFieldFromExpressionAsync([QixName("qName")] string name, [QixName("qExpr")] string expr)
    
  
```

### Parameters

| Type | Name | Description |
| --- | --- | --- |
| System.String | name | Name of the field. |
| System.String | expr | Expression value.<br>It is not possible to use all aggregation functions. For example, you cannot add a field on the fly with an expression that uses the `Sum` or `Count` aggregation functions. |

### Returns

| Type | Description |
| --- | --- |
| System.Threading.Tasks.Task&lt;System.Boolean&gt; |  |

### Implements

[IApp.AddFieldFromExpressionAsync(String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.IApp.AddFieldFromExpressionAsync.htm#Qlik_Engine_IApp_AddFieldFromExpressionAsync_System_String_System_String_)

### Remarks

The expression of a field on the fly is persisted but not its values.

[](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm) [](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm)

## AddFieldFromExpressionAsync(AsyncHandle, String, String)

Adds a field on the fly.

### Declaration

```

          public Task<bool> AddFieldFromExpressionAsync(AsyncHandle asyncHandle, [QixName("qName")] string name, [QixName("qExpr")] string expr)
    
  
```

### Parameters

| Type | Name | Description |
| --- | --- | --- |
| [AsyncHandle](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.AsyncHandle.htm) | asyncHandle | Handle to asynchronous method request |
| System.String | name | Name of the field. |
| System.String | expr | Expression value.<br>It is not possible to use all aggregation functions. For example, you cannot add a field on the fly with an expression that uses the `Sum` or `Count` aggregation functions. |

### Returns

| Type | Description |
| --- | --- |
| System.Threading.Tasks.Task&lt;System.Boolean&gt; |  |

### Implements

[IApp.AddFieldFromExpressionAsync(AsyncHandle, String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.IApp.AddFieldFromExpressionAsync.htm#Qlik_Engine_IApp_AddFieldFromExpressionAsync_Qlik_Engine_AsyncHandle_System_String_System_String_)

### Remarks

The expression of a field on the fly is persisted but not its values.

[](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm) [](https://help.qlik.com/en-US/sense-developer/Subsystems/NetSDKAPIref/Content/Qlik.Engine.App.AddFieldFromExpressionAsync.htm)

## AddFieldFromExpressionAsync&lt;T&gt;(AsyncHandle, Func&lt;Response, T&gt;, String, String)

Adds a field on the fly.

### Declaration

```
public Task<T> AddFieldFromExpressionAsync<T>(AsyncHandle asyncHandle, Func<Response, T> onResult, [QixName("qName")] string name, [QixName("qExpr")] string expr)
```

### Parameters

| Type | Name | Description |
| --- | --- | --- |
| [AsyncHandle](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.AsyncHandle.htm) | asyncHandle | Handle to asynchronous method request |
| System.Func&lt;[Response](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.Communication.IO.Response.htm), T&gt; | onResult | Continuation function |
| System.String | name | Name of the field. |
| System.String | expr | Expression value.<br>It is not possible to use all aggregation functions. For example, you cannot add a field on the fly with an expression that uses the `Sum` or `Count` aggregation functions. |

### Returns

| Type | Description |
| --- | --- |
| System.Threading.Tasks.Task&lt;T&gt; |  |

### Type Parameters

| Name | Description |
| --- | --- |
| T |  |

### Implements

[IApp.AddFieldFromExpressionAsync<T>(AsyncHandle, Func<Response, T>, String, String)](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/NetSDKAPIref/Content/Qlik.Engine.IApp.AddFieldFromExpressionAsync.htm#Qlik_Engine_IApp_AddFieldFromExpressionAsync__1_Qlik_Engine_AsyncHandle_System_Func_Qlik_Engine_Communication_IO_Response___0__System_String_System_String_)

### Remarks

The expression of a field on the fly is persisted but not its values.