Add References and Set a License - WinForms C#

This tutorial shows how to use the LEADTOOLS SDK in a WinForms C# application and create a project, add references, and set the license.

Summary This tutorial covers how to set a license in a WinForms C# application.
Completion Time 10 minutes
Visual Studio Project Download tutorial project (7 KB)
Platform WinForms C# Application
IDE Visual Studio 2017, 2019
Development License Download LEADTOOLS
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Required Knowledge

Before any functionality from the SDK can be leveraged, a valid runtime license will have to be set.

For instructions on how to obtain a runtime license refer to Obtaining a License.

Create the Project

Launch Visual Studio and select Create a new project.

Creating a new Visual Studio project.

Select Windows Forms App (.NET Framework) and click Next.

Creating a new Winforms App .NET Framework.

Add the project name, specify the location where the project to be saved to and the other project details, then click Create.

Adding the Visual Studio project name and location.

Add LEADTOOLS References

Add the necessary LEADTOOLS references. The references needed depend upon the purpose of the project. References can be added by one or the other of the following two methods (but not both).

NuGet Reference - Add LEADTOOLS References via NuGet

Right-click the C# project in the Solution Explorer and select Manage NuGet Packages...

Selecting Manage NuGet Packages.

Browse for LEADTOOLS, then select any of the LEADTOOLS NuGet packages and install it. Accept LEAD's End User License Agreement.

Installing LEADTOOLS NuGet packages.

Local Reference - Add Reference to LEADTOOLS Local DLLs

To add the LEADTOOLS references locally, perform the following steps:

In the Solution Explorer, right-click References, and select Add Reference.

Adding local assembly reference.

In the Reference Manager, select Browse and then navigate to the directory where the LEADTOOLS Assemblies are located: <INSTALL_DIR>\LEADTOOLS22\Bin\Dotnet4\x64

Select and add Leadtools.dll, then click OK.

Adding reference to Leadtools.dll.

Add the Set License Code

Now that the LEADTOOLS references have been added to the project, coding can begin. The License unlocks the LEADTOOLS features needed for the project. It must be set before any toolkit function is called. The exact function called depends on the platform used. For details, refer to Setting a Runtime License.

There are two types of runtime licenses:

Right-click on Form1.cs in the Solution Explorer, and select View Code to bring up the code behind the form. Add the following statements to the using block.

using System.Windows.Forms; 
using System.IO; 
using Leadtools; 

In the Form1 class add a new method called SetLicense() and call it in the Form1() constructor. Add the code below to properly set your LEADTOOLS runtime license.

public partial class Form1 : Form 
   public Form1() 
   static void SetLicense() 
      string license = @"C:\LEADTOOLS22\Support\Common\License\LEADTOOLS.LIC"; 
      string key = File.ReadAllText(@"C:\LEADTOOLS22\Support\Common\License\LEADTOOLS.LIC.KEY"); 
      RasterSupport.SetLicense(license, key); 
      if (RasterSupport.KernelExpired) 
         MessageBox.Show("License file invalid or expired."); 
         MessageBox.Show("License file set successfully"); 

Run the Project

Run the project by pressing F5, or by selecting Debug -> Start Debugging.

If the steps are followed correctly, the application runs and a message box displays License file set successfully.

Message box indicating license has been set successfully.


This tutorial showed how to create a new C# .NET Framework WinForms Project, add references via NuGet or local LEADTOOLS DLLs, and set the license.

This is the basis for all C# .NET Framework Winforms applications using the LEADTOOLS SDK. All functionality in the SDK is unlocked via setting a license. SetLicense must be called before calling any other LEADTOOLS SDK methods.

After the SDK is purchased, the evaluation license can be replaced with a valid release license to disable the Nag Message.

See Also

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.