Set slide style

VSTO
Spire.Presentation
Download Sample Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using PowerPoint = Microsoft.Office.Interop.PowerPoint;
using Office = Microsoft.Office.Core;

namespace VSTO
{
    public partial class ThisAddIn
    {
        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            //Create empty presentation
            PowerPoint.Presentation ppt = this.Application.Presentations.Add();

            //Add a blank slide
            PowerPoint.Slide slide = ppt.Slides.Add(1, PowerPoint.PpSlideLayout.ppLayoutBlank);

            //Add shape to slide
            PowerPoint.Shape shape = slide.Shapes.AddShape(Office.MsoAutoShapeType.msoShapeRectangle, 300, 100, 300, 100);

            //Set the style of slide
            shape.Line.Style = Office.MsoLineStyle.msoLineSingle;
            shape.Line.Weight = 5;
            //Border color
            shape.Line.ForeColor.RGB = 0x000000CC;
            //Background color
            shape.Fill.ForeColor.RGB = 0x00000000;

            //Set the style of slide
            slide.BackgroundStyle = Office.MsoBackgroundStyleIndex.msoBackgroundStylePreset1;
            slide.Background.Fill.ForeColor.RGB = 0x00CCFFCC;

            //Save the file
            ppt.SaveAs("Style.pptx");
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }
        
        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Spire.Presentation;
using System.Drawing;
using Spire.Presentation.Drawing;

namespace Spire.Presentation
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create ppt document
            Presentation ppt = new Presentation();

            //Get the first slide
            ISlide slide = ppt.Slides[0];

            //Add shape to slide
            IShape shape = slide.Shapes.AppendShape(ShapeType.Rectangle, new System.Drawing.RectangleF(200, 50, 300, 100));
            
            //Set the style of shape
            shape.Line.FillType = Spire.Presentation.Drawing.FillFormatType.Solid;            
            shape.Fill.FillType = Spire.Presentation.Drawing.FillFormatType.Solid;
            //Background color
            shape.Fill.SolidColor.Color = Color.Black;
            //Border color
            shape.Line.SolidFillColor.Color = Color.Red;
            shape.Line.Width = 5;

            //Set the style of slide
            slide.SlideBackground.Type = BackgroundType.Custom;
            slide.SlideBackground.Fill.FillType = Spire.Presentation.Drawing.FillFormatType.Solid;
            slide.SlideBackground.Fill.SolidColor.Color = Color.DarkGray;

            //Save and Launch
            ppt.SaveToFile("Style.pptx", FileFormat.Pptx2010);
            System.Diagnostics.Process.Start("Style.pptx");

        }
    }
}

SetStyle.zip