Dear Bijesh,
Thanks for considering Aspose.Slides for .NET
To add quotation marks, you need to use escape sequence, you cannot add it directly. For example in C#, you will use
textFrame.Text = "This is a quotation mark \". ";
And in VB.NET
textFrame.Text = "This is a quotation mark "". ";
Please also see this code and the output presentation generated by it, which I have attached.
Code - C#
Presentation srcPres = new Presentation();
Slide srcSld = srcPres.GetSlideByPosition(1);
//Create a rectangle and hide its lines
Aspose.Slides.Rectangle rect = srcSld.Shapes.AddRectangle(300, 400, 5000, 1);
rect.LineFormat.ShowLines = false;
//Create a text box by adding textframe inside rectangle
TextFrame tf = rect.AddTextFrame("");
//Textframe will automatically wrap any line that exceeds its width
tf.WrapText = true;
//Textframe will grow the rectangle height if requires
tf.FitShapeToText = true;
//Add some text using TextFrame.TextProperty
tf.Text = "\"Double Quotes\"";
//Add some text using Paragraph
//Clone the previous paragraph and change its text, and then add it
Paragraph para = new Paragraph(tf.Paragraphs[0]);
para.Text = "\"Double Quotes using Paragraph\"";
tf.Paragraphs.Add(para);
//Add some text using Portion
//Clone the previous portion inside the newly added paragraph, and change its text
//and then add it
Portion port = new Portion(para.Portions[0]);
port.Text = " \"Double Quotes using Portion\"";
para.Portions.Add(port);
//Write the presentation on disk
srcPres.Write(@"c:\outPres.ppt");