I want to abort running deployment via TFS API with C#.
You can use .NET client libraries for Azure DevOps Services (and TFS).
This code snippet cancel a release:
string projectName = "";
int releaseId = 1;
string collectionUri = "";
VssCredentials creds = new VssClientCredentials();
creds.Storage = new VssClientCredentialStorage();
// Connect to Azure DevOps Services
VssConnection connection = new VssConnection(new Uri(collectionUri), creds);
ReleaseHttpClient releaseClient = connection.GetClient<ReleaseHttpClient>();
ReleaseUpdateMetadata releaseUpdateMetadata = new ReleaseUpdateMetadata()
{
Comment = "Abandon the release",
Status = ReleaseStatus.Abandoned
};
// Abandon a release
WebApiRelease updatedRelease = releaseClient.UpdateReleaseResourceAsync(releaseUpdateMetadata, projectName, releaseId ).Result;
More details and examples you can find here.