# Try Catch

> `System.Activities.Statements.TryCatch`

`System.Activities.Statements.TryCatch`

## Description

Catches a specified exception type in a sequence or activity, and either displays an error notification or dismisses it and continues the execution.

There is no limit to how many **Catches** you can use in a **Try Catch** activity. This activity requires at least one catch to be added.

## Project compatibility

**Windows - Legacy** | **Windows** | **Cross-platform**

## Configuration

The activity body contains three fields:

* **Try** - The activity performed which has a chance of throwing an error.
* **Catches** - The activity or set of activities to be performed when an error occurs.
  + **Exception** - The exception type to look for. You can add multiple exceptions.
* **Finally** - The activity or set of activities to be performed after the **Try** and **Catches** blocks are executed. This section is executed only when no exceptions are thrown or when an error occurs and is caught in the **Catches** section.
  
  ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-183441-d8e0c340.webp)

:::note
* If an activity is included in the **Try** section, and the value of the **ContinueOnError** property is True, no error is caught when the project is executed.
* The **Try Catch** activity does not catch fatal exceptions such as:
  + FatalException
  + OutOfMemoryException
  + ThreadAbortException
  + FatalInternalException
:::

## Properties

#### **Common**

* **DisplayName** - The display name of the activity.

#### **Misc**

* **Private** - If selected, the values of variables and arguments are no longer logged at Verbose level.
  :::note
  Pressing “Ctrl + T” places the selected activity inside the **Try** section of a **Try Catch** activity.
  :::

## Example of using the Try Catch activity

To better understand the importance of the **Try Catch** activity, we created an automation that gathers multiple names from a random name generator website and writes them in an Excel spreadsheet.

[You can download the initial workflow here.](https://www.uipath.com/hubfs/Documentation/WorkflowExamples/Example-of-Using-the-Try-Catch-Activity-Initial.zip)

:::note
Due to a technical limitation, the reported exception Source in a Try-Catch scenario might differ if the exception occurs inside of an invoked workflow.
:::

A **Build Data Table** activity is used to create a table in which to store the gathered names. Another workflow is invoked to read the web data. Finally, an **Excel application scope** activity is used to write the gathered information in the Excel file.

First of all, let’s run the automation to check for any errors. Notice that a **Workflow Exception** window is displayed. The **Exception Type** field tells us what the problem is. This is used in the **Catches** section of a **Try Catch** as the exception type to look for during the workflow execution.

  ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-180832-53fd6e52.webp)

As you can see in the screenshot above, when running the example workflow, there seems to be a problem with the **Attach Browser** container selector. The issue is that the selector fails to identify the browser window with the “Generate a Random Name - Fake Name Generator” name.

To catch this exception, we need to perform the following:

1. Drag the **Try Catch** activity from the **Activities** panel above the **Invoke workflow** activity.
2. Place the **Invoke workflow** activity in the **Try** section of the **Try Catch** activity. This watches the **Invoke workflow** activity in case it throws an error.
   
   ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-178283-e21f4b89.webp)
3. In the **Catches** section, select the `UiPath.Core.SelectorNotFoundException` exception from the drop-down. If it’s not there, you can find it in the [Browse and Select a .Net Type](https://docs.uipath.com/studio/docs/managing-variables#section-browsing-for-net-variable-types) window.
   
   ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-180212-3fa09bda.webp)
4. Optionally, you can add a **Message Box** activity in the **Catches** section. You can fill in the **Content** field with an informative message between quotes, in our case “Internet Explorer was closed. It will now open to continue the workflow execution”. This means that whenever the exception is caught, this message box is displayed, to inform the user that the browser is about to open so that the workflow is successfully executed.
   
   ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-179612-e317e97b.webp)
5. Drag the **Element Exists** activity in the **Finally** section. This is used to check if Internet Explorer is open on the page of interest, https://www.fakenamegenerator.com.
6. Open Internet Explorer and access the previously mentioned page.
7. Use the **Indicate on screen** functionality to select the Internet Explorer window.
8. Select the **Element Exists** activity and edit its selector so that it looks like this `<wnd app='iexplore.exe' title='Generate a Random Name - Fake Name Generator - Internet Explorer' />`. This selector ensures that the **Element Exists** activity only looks for an active Internet Explorer window in which the aforementioned page is open.
9. In the **Output** property, create a variable with a relevant name, such as `browser`. This is a boolean variable which helps you determine whether or not Internet Explorer is active on the indicated page.
10. Add an **If** activity under the **Element Exists** activity. This is used to open Internet Explorer if it’s closed, and continue the workflow otherwise.
11. In the **Condition** field, write `browser=false`. This condition is used to verify if the browser is opened or not, and perform other actions, based on its value.
12. Drag an **Open Browser** activity in the **Then** section. If the **Condition** is met (the browser is closed), then the **Open Browser** activity is used to open it, without affecting the workflow.
13. In the **Url** field type https://www.fakenamegenerator.com.
14. Leave the **Else** section empty so that the workflow continues as expected if Internet Explorer is already opened on the indicated website.
    
    ![docs image](https://dev-assets.cms.uipath.com/assets/images/activities/activities-docs-image-179040-ad495199.webp)
15. Run the workflow and notice one of the following:
  * If Internet Explorer is closed - The user is informed that Internet Explorer is about to open so the workflow can continue. The browser opens, all expected data is gathered and written to the Excel file.
  * If Internet Explorer is open - The workflow is executed as expected. 

[Download example](https://www.uipath.com/hubfs/Documentation/WorkflowExamples/Example-of-Using-the-Try-Catch-Activity-Final.zip)