This tutorial shows how to use the LEADTOOLS SDK in a WinForms C# application and create a project, add references, and set the license.
|This tutorial covers how to set a license in a WinForms C# application.
|Visual Studio Project
|Download tutorial project (7 KB)
|WinForms C# Application
|Visual Studio 2017, 2019
|Try it in another language
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.
Launch Visual Studio and select Create a new project.
Select Windows Forms App (.NET Framework) and click Next.
Add the project name, specify the location where the project to be saved to and the other project details, then click Create.
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).
Right-click the C# project in the Solution Explorer and select Manage NuGet Packages...
Browse for LEADTOOLS, then select any of the LEADTOOLS NuGet packages and install it. Accept LEAD's End User License Agreement.
To add the LEADTOOLS references locally, perform the following steps:
In the Solution Explorer, right-click References, and select Add Reference.
In the Reference Manager, select Browse and then navigate to the directory where the LEADTOOLS Assemblies are located:
Select and add
Leadtools.dll, then click OK.
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:
Form1.cs in the Solution Explorer, and select View Code to bring up the code behind the form. Add the following statements to 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
static void SetLicense()
string license = @"C:\LEADTOOLS22\Support\Common\License\LEADTOOLS.LIC";
string key = File.ReadAllText(@"C:\LEADTOOLS22\Support\Common\License\LEADTOOLS.LIC.KEY");
MessageBox.Show("License file invalid or expired.");
MessageBox.Show("License file set successfully");
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.
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.