extract-text-from-presentation.cs

//Instatiate Presentation class that represents a PPTX file
Presentation pptxPresentation = new Presentation("demo.pptx");

//Get an Array of ITextFrame objects from all slides in the PPTX
ITextFrame[] textFramesPPTX = Aspose.Slides.Util.SlideUtil.GetAllTextFrames(pptxPresentation, true);

//Loop through the Array of TextFrames
for (int i = 0; i < textFramesPPTX.Length; i++)
{
	//Loop through paragraphs in current ITextFrame
	foreach (IParagraph para in textFramesPPTX[i].Paragraphs)
	{
		//Loop through portions in the current IParagraph
		foreach (IPortion port in para.Portions)
		{
			//Display text in the current portion
			Console.WriteLine(port.Text);

			//Display font height of the text
			Console.WriteLine(port.PortionFormat.FontHeight);

			//Display font name of the text
			if (port.PortionFormat.LatinFont != null)
				Console.WriteLine(port.PortionFormat.LatinFont.FontName);
		}
	}
}

extract-text-from-slide.cs

//Instatiate PresentationEx class that represents a PPTX file
Presentation pptxPresentation = new Presentation("demo.pptx");

//Get an Array of TextFrameEx objects from the first slide
ITextFrame[] textFramesSlideOne = SlideUtil.GetAllTextBoxes(pptxPresentation.Slides[0]);

//Loop through the Array of TextFrames
for (int i = 0; i < textFramesSlideOne.Length; i++)
{
    //Loop through paragraphs in current TextFrame
    foreach (Paragraph para in textFramesSlideOne[i].Paragraphs)
    {
        //Loop through portions in the current Paragraph
        foreach (Portion port in para.Portions)
        {
            //Display text in the current portion
            Console.WriteLine(port.Text);

            //Display font height of the text
            Console.WriteLine(port.PortionFormat.FontHeight);

            //Display font name of the text
            Console.WriteLine(port.PortionFormat.LatinFont.FontName);
        }
    }
}