C# public class error object reference not set to an instance of an object

Question

I have the data being pulled from a separate c# file called data. The class for data is Version. I used a separate class to make my Label class. When I compile it, I get the, Object reference not set to an instance of an object. I am not sure why the error is happening. Since it is tied to a database.

public Data Version { get; set; }
    public Label Label { get; set; }

    public Form1()
    {
        InitializeComponent();

        CmboBoxLabel.Items.Add(new Label(Version.LabelName, Version.LabelCode));
    }

If you want any of the class code let me know.

Data Version Class

public class Data
{
    public Data()
    {
        LabelName = "";
        LabelCode = -1;
        LabelStock = -1;

    }

    public string LabelName { get; set; }
    public Int32 LabelCode { get; set; }
    public Int32 LabelStock { get; set; }

    public ODSData_XXXXX.TrayLabelReferenceRow toDataRow()
    {
        ODSData_XXXX.TrayLabelReferenceRow row = null;
        row.LabelName = this.LabelName;
        row.LabelCode = this.LabelCode;
        row.LabelStock = this.LabelStock;
        return row;
    }

    public static Data loadFromDataRow(ODSData_XXXX.TrayLabelReferenceRow row)
    {
        Data Version = new Data();
        Version.LabelName = row.LabelName;
        Version.LabelCode = row.LabelCode;
        Version.LabelStock = row.LabelStock;

        return Version;
    }
}

Answer 1

You're not instantiating Version anywhere in the scope of where you're wanting to use the variable. Do something like this:

public Label Label;

public Form1()
{
    Data version = new Data(); // this creates and instantiates a new Data object named Version
    InitializeComponent();

    CmboBoxLabel.Items.Add(new Label(version.LabelName, version.LabelCode));
}

Of course, after you create the version , you'll need to populate it's properties however you would like. Ultimately, you'll want to look more into Classes and Properties and how they work.