# Using LexFloatClient with C\#

## Adding licensing to your app

After you've added a product for your app in the admin portal, you will need to do the following things:

* Note the product id for the product (from the actions menu in the table).
* Download the example project from [Github](https://github.com/cryptlex/lexfloatclient-dotnet/tree/master/examples).

The product id is the identifier of your product that is to be used in the code. The product id of the LexFloatServer and LexFloatClient must match.

### Adding the library to your app

LexFloatClient wrapper for C# can be easily installed through [nuget](https://www.nuget.org/packages/Cryptlex.LexFloatClient):

```bash
Install-Package Cryptlex.LexFloatClient
# or
dotnet add package Cryptlex.LexFloatClient
```

{% hint style="info" %}
**LexFloatClient** requires the Microsoft Visual C++ 2015 (or later) Runtime on older Windows versions such as Windows 7, 8, or Server 2008/2012. If not already installed, install it from the official [Visual C++ Redistributable](https://www.microsoft.com/en-in/download/details.aspx?id=48145) or include the required DLLs with your installer.
{% endhint %}

### Setting product id

The first LexFloatClient API function you need to use in your code is `SetHostProductId()`. It sets the product id of the product you will be adding licensing to. 

```csharp
LexFloatClient.SetHostProductId("PASTE_PRODUCT_ID");
```

### Requesting floating license

To receive a floating license, you will use `SetHostUrl()`, `SetFloatingLicenseCallback()` and `RequestFloatingLicense()`LexFloatClient API methods. It sets the LexFloatServer address, the callback for status notifications, contacts the server and receives the floating license.

```csharp
private void leaseBtn_Click(object sender, EventArgs e)
{
    try
    {
        LexFloatClient.SetHostProductId("PASTE_YOUR_PRODUCT_ID");
        LexFloatClient.SetHostUrl("http://localhost:8090");
        LexFloatClient.SetFloatingLicenseCallback(LicenceRenewCallback);
        LexFloatClient.RequestFloatingLicense();
        this.statusLabel.Text = "License leased successfully!";
    }
    catch (LexFloatClientException ex)
    {
        this.statusLabel.Text = "Error code: " + ex.Code.ToString() + " Error message: " + ex.Message;
    }
}
```

The above code can be executed every time user starts the app or needs a new license.

### Renewing license lease

License lease automatically renews itself in a background thread. When a license is renewed or fails to renew, the callback is invoked (from the background thread).

```csharp
private void LicenceRenewCallback(uint status)
{
    switch (status)
    {
        case LexFloatStatusCodes.LF_OK:
            this.statusLabel.Text = "The license lease has renewed successfully.";
            break;
        case LexFloatStatusCodes.LF_E_LICENSE_NOT_FOUND:
            this.statusLabel.Text = "The license expired before it could be renewed.";
            break;
        case LexFloatStatusCodes.LF_E_LICENSE_EXPIRED_INET:
            this.statusLabel.Text = "The license expired due to network connection failure.";
            break;
        default:
            this.statusLabel.Text = "The license renew failed due to other reason. Error code: " + status.ToString();
            break;
    }
}
```

### Dropping floating license

When your user is done using the app, the app should send a request to free the license, thereby making it available to other users. If the app doesn't, the license becomes (zombie) useless until lease time is over.

```csharp
private void dropBtn_Click(object sender, EventArgs e)
{
    try
    {
        if (!LexFloatClient.HasFloatingLicense())
        {
            return;
        }
        LexFloatClient.DropFloatingLicense();
        this.statusLabel.Text = "License dropped successfully!";
    }
    catch (LexFloatClientException ex)
    {
        this.statusLabel.Text = "Error code: " + ex.Code.ToString() + " Error message: " + ex.Message;
    }
}
```

The above code should be executed every time user closes the app.

## Need more help

In case you need more help with adding LexFloatClient to your app, we'll be glad to help you make the integration. You can either post your questions on our [support forum](https://forums.cryptlex.com) or can contact us through [email](mailto:support@cryptlex.com?Subject=Using%20LexFloatClient).