如何使用ML.NET ColumnDropper删除列

Question

我是机器学习的新手，我正在尝试使用Microsoft.ML，尤其是框架的Transform部分。 有人可以告诉我我在做什么错。我无法从数据集中删除列？

var loader = new Microsoft.ML.Data.TextLoader(TrainDataPath).CreateFrom<BloodDonateData>(useHeader: true, separator: ',');
int columnsCount = 5;
using (var environment = new TlcEnvironment())
{
    Experiment experiment = environment.CreateExperiment();
    ILearningPipelineDataStep pipelineDataStep = loader.ApplyStep(null, 
    experiment) as ILearningPipelineDataStep;
    experiment.Compile();
    loader.SetInput(environment, experiment);
    experiment.Run();

    ColumnDropper columnDropper = new ColumnDropper
    {
        Column = new string[] { "Time" },
        Data = pipelineDataStep.Data
    };
    columnDropper.ApplyStep(pipelineDataStep, experiment);

    var data = experiment.GetOutput(columnDropper.Data);

    using (var cursor = data.GetRowCursor(a => true))
    {
       // print data..
    }
}