Can't install NuGet Packages

Question

For the second day I've been trying to install a NuGet Package, specifically Microsoft.Data.SqlClient, but the output I get is:

NU1100: Unable to resolve 'Microsoft.Data.SqlClient (>= 5.1.1)' for 'net7.0-windows7.0'. PackageSourceMapping is enabled, the following source(s) were not considered: Microsoft Visual Studio Offline Packages, Package source. Package restore failed. Rolling back package changes for 'workers'.

I've tried changing versions, starting the project from scratch, changing NuGet sources, but nothing helped. I downloaded the package separately and added the source, but it still won't install.

Answer 1

It looks like you're using .NET 7, however, it's unclear if you're using Visual Studio 2022. Nonetheless, one can create a new project and add the NuGet package without Visual Studio using dotnet new , dotnet sln, and dotnet add package.

• Download/install the .NET SDK
• Open a cmd window

To see installed SDKs:

• dotnet --info

To see available templates

• dotnet new list

Create a new WinForms Application project (name: WinFormsTest):

• dotnet new winforms --framework <TargetFramework> --output <fully-qualified path>

For example, to create a new project in a subfolder of your Documents folder:

Note: Below you'll notice two subdirectories with the same name (WinFormsTest). The first one is for the solution and the subfolder with the same name is for the project - this is the same structure Visual Studio creates.

 dotnet new winforms --framework net7.0 --output "%UserProfile%\Documents\Projects\WinFormsTest\WinformsTest"

see TargetFramework

Create solution file:

dotnet new sln --name "WinFormsTest" --output "%UserProfile%\Documents\Projects\WinFormsTest" --project "%UserProfile%\Documents\Projects\WinFormsTest\WinformsTest\WinFormsTest.csproj"

Add Project to Solution File:

dotnet sln "%UserProfile%\Documents\Projects\WinformsTest" add "%UserProfile%\Documents\Projects\WinformsTest\WinformsTest\WinformsTest.csproj"

Search for desired NuGet package, for example NuGet package Microsoft.Data.SqlClient

Download and add desired NuGet package to project (ex: Microsoft.Data.SqlClient)

dotnet add "%UserProfile%\Documents\Projects\WinFormsTest\WinformsTest\WinformsTest.csproj" package "Microsoft.Data.SqlClient"

or

dotnet add "%UserProfile%\Documents\Projects\WinFormsTest\WinformsTest\WinformsTest.csproj" package "Microsoft.Data.SqlClient" --source "https://api.nuget.org/v3/index.json"

For additional information see dotnet add package, dotnet nuget add source, and Common NuGet configurations.

To Build/Run Application:

dotnet run --project "%UserProfile%\Documents\Projects\WinFormsTest\WinformsTest\WinformsTest.csproj"

Use your favorite editor to develop/modify the Windows Forms Application (you may consider using Visual Studio).