protected override void RegisterInputParams(GH_Component.GH_InputParamManager pManager) { pManager.AddNumberParameter("Numbers", "N", "List of numbers", GH_ParamAccess.list); } protected override void SolveInstance(IGH_DataAccess DA) { ListIn the above example, the input parameter is a list of numbers that is retrieved using the IGH_DataAccess.GetDataList method. The retrieved data is then used for further processing. In summary, the IGH_DataAccess.GetDataList method is a useful method for retrieving a list of data items provided by the Grasshopper library package in C#.numbers = new List (); DA.GetDataList(0, numbers); // Use the numbers list here }