NuGet can only install TXTextControl.TextControl.WinForms.SDK from a source that has it, and the package is not published on nuget.org. There are three such sources: the local source that the setup installs, the Text Control Private NuGet Feed, and a feed of your own that mirrors the package. How to set up each of them, and which one fits a development machine or a build server, is shown below.

Which Source to Use

Source	Where it is	Use it for
Text Control Offline Packages	A folder on your development machine, installed by the setup	Development in Visual Studio
Text Control Private NuGet Feed	`https://www.textcontrol.com/nuget/v3/index.json`, with your email address and an API token	Build servers and CI/CD pipelines
Your own feed	For example Azure Artifacts, with the package pushed from the offline folder	Build systems in your organization

The package from the private feed is meant for compiling only. A development machine needs the setup, which also provides the offline source. See Installing the Product.

Text Control Offline Packages

The setup of the full version installs the package into the folder C:\Program Files (x86)\Text Control GmbH\NuGetPackages and makes it available in Visual Studio as the package source Text Control Offline Packages. In Visual Studio, you select it in the Package source list of the NuGet Package Manager. See Installing and Updating Packages.

For builds outside Visual Studio, for example with the .NET CLI, add the folder to the nuget.config file in the folder of your project or solution:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="TextControlLocal" value="C:\Program Files (x86)\Text Control GmbH\NuGetPackages" />
  </packageSources>
</configuration>

The value can also be another folder or the URL of your own package repository to which you copied the package.

Text Control Private NuGet Feed

The private feed is available to customers with an active subscription. It authenticates you with the email address of the developer a serial number is assigned to and an API token, and it offers only the packages and versions that developer is licensed for. The license is added to each package on the server before it is downloaded.

In the NuGet Package Manager of Visual Studio, the feed is the package source TextControl. The following screenshot shows it with the packages of a developer who is licensed for several products, TXTextControl.TextControl.WinForms.SDK among them:

Get Your Credentials

The owner of the Text Control account assigns a serial number to you, as described in Assign a License to a Developer.
For a serial number that includes NuGet access, an API token is created automatically, and you receive an email with the serial number and a download link for your personal nuget.config file.
An automatically created token is valid for 365 days and is extended when the serial number is assigned again. Under Manage API tokens, a token can also be created manually, valid for 1 to 730 days.

Add nuget.config to the Project

Copy the downloaded nuget.config into the root folder of your project. It has this structure:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <clear />
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
    <add key="TextControl" value="https://www.textcontrol.com/nuget/v3/index.json" />
  </packageSources>
  <packageSourceCredentials>
    <TextControl>
      <add key="Username" value="YOUR_EMAIL" />
      <add key="ClearTextPassword" value="YOUR_API_TOKEN" />
    </TextControl>
  </packageSourceCredentials>
</configuration>

<clear /> removes the sources of other configuration files, so that only nuget.org and the Text Control feed are used.
The package source is named TextControl. Select it in Visual Studio, or pass it to the .NET CLI.
Keep the file out of source control. It contains your credentials. On a build server, store the email address, the API token and the feed URL as secrets and create nuget.config during the build. See Build Servers.

If Visual Studio does not pick up the file, see Visual Studio Doesn't Use the Private Feed in Troubleshooting.

The blog article Text Control Private NuGet Feed describes the feed and pipeline configurations for GitHub Actions, GitLab, Azure DevOps, Jenkins, Bitbucket and TeamCity.

Your Own Feed

The license agreement allows an internal mirror of the NuGet packages for your licensed developers and your build systems, but not republishing them for others. With Azure DevOps, for example:

In Artifacts, click Create Feed, then Connect to Feed and NuGet.exe, and copy the feed path.
Push the package from the offline folder, C:\Program Files (x86)\Text Control GmbH\NuGetPackages on a development machine, to the feed with nuget.exe push, as the blog article Azure Pipelines with TX Text Control .NET for WPF and Windows Forms 32.0 with Azure DevOps and Artifacts shows.
Add the feed to the nuget.config of your project, with a personal access token as the credential.

Build Windows Forms projects on a Windows build agent, as the article does.

Configuring Package Sources