I came across couple of questions from Internet about how to programmatically create a Gannt view on a custom SharePoint list. So, here is an answer to these questions.



1. First of all, create a custom list from a SharePoint UI.

2. On the menu of the newly created custom list, click Settings->Create Column.

3. Create a column for Start Date with "Date and Time" type with Date Only as a format (see the picture below). The column name doesn't need to be exactly same.

 



4. Create a column for End Date with "Date and Time" type with Date Olnly as a format.
5.Create a column for PercentComplete with "Number" type. Set Min to 0 and Max to 100. Set number of decimal place to 0, and check the "Show as percentage (for example, 50%)" option. See the picture below.


Now, run the following code to create a Gannt view.


using System;
using System.Text;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
namespace ConsoleApplication1
{
 class Program
 {
    static void Main(string[] args)
    {
        using(SPSite site = new SPSite("[site url]"))
        using (SPWeb web = site.OpenWeb())
        {
          SPList list = web.Lists["CustomList"];
          SPViewCollection views = list.Views;
          System.Collections.Specialized.StringCollection viewFields = 
		new System.Collections.Specialized.StringCollection();
          viewFields.Add("Title");
          SPView view = views.Add("Gannt Test", 
		viewFields, String.Empty, 100, true, false, 
		SPViewCollection.SPViewType.Gantt, false);
         view.ViewData = @"<FieldRef Name=""StartDate"" Type=""GanttStartDate"" />
		<FieldRef Name=""DueDate"" Type=""GanttEndDate"" />
		<FieldRef Name=""Title"" Type=""GanttTitle"" />
		<FieldRef Name=""PercentComplete"" 
		Type=""GanttPercentComplete"" />";
               
          view.Update();
        }
    }
 }
}

The key point on the code is that you need to use GanttStartDate, GanntEndDate, GanntDueDate and GanntPercentComplete as types of FieldRefs for ViewData.