Question

I am using openXML and C# to generate a powerpoint slide but I can’t seem to figure out how to change / set the text size and color. Is this possible and are there any example as I can’t seem to find any with googling?

I am building out a table (similar to this: http://blogs.msdn.com/b/brian_jones/archive/2009/08/13/adding-repeating-data-to-powerpoint.aspx) and I want to change a number of things in each cell (fontsize, font color, backcolor of cell).

Answer 1

Your comments state this Formatting is for a Table inside a PowerPoint slide.

Assumptions
I am assuming you have already created the table, table rows, table cells, and display text.
Also assuming you have everything working and now you want to add formatting.

If you want to format your Text and Cells, you may do so using the following:

//Create the TableCell for the PowerPoint table you are building.
A.TableCell tableCell3 = new A.TableCell();
A.TextBody textBody5 = new A.TextBody();
A.BodyProperties bodyProperties5 = new A.BodyProperties();//Created but not modified.
A.ListStyle listStyle5 = new A.ListStyle();//Created but not modified.
A.Paragraph paragraph5 = new A.Paragraph();

//First Word: "Hello" with Font-Size 60x and Font-Color Green.
A.Run run1 = new A.Run();
A.RunProperties runProperties1 = new A.RunProperties() { Language = "en-US", FontSize = 6000, Dirty = false, SmartTagClean = false };//Set Font-Size to 60px.
A.SolidFill solidFill1 = new A.SolidFill();
A.RgbColorModelHex rgbColorModelHex1 = new A.RgbColorModelHex() { Val = "00B050" };//Set Font-Color to Green (Hex "00B050").
solidFill1.Append(rgbColorModelHex1);
runProperties1.Append(solidFill1);
A.Text text1 = new A.Text();
text1.Text = "Hello";
run1.Append(runProperties1);
run1.Append(text1);

//Second Word: "World" with Font-Size 60x and Font-Color Blue.
A.Run run2 = new A.Run();
A.RunProperties runProperties2 = new A.RunProperties() { Language = "en-US", FontSize = 6000, Dirty = false, SmartTagClean = false };//Set Font-Size to 60px.
A.SolidFill solidFill2 = new A.SolidFill();
A.RgbColorModelHex rgbColorModelHex2 = new A.RgbColorModelHex() { Val = "0070C0" };//Set Font-Color to Blue (Hex "0070C0").
solidFill2.Append(rgbColorModelHex2);
runProperties2.Append(solidFill2);
A.Text text2 = new A.Text();
text2.Text = " World";
run2.Append(runProperties2);
run2.Append(text2);

//This element specifies the text run properties that are to be used if another run is inserted after the last run specified.
//This effectively saves the run property state so that it can be applied when the user enters additional text.
//If this element is omitted, then the application can determine which default properties to apply.
//It is recommended that this element be specified at the end of the list of text runs within the paragraph so that an orderly list is maintained.
//  Source: http://msdn.microsoft.com/en-us/library/documentformat.openxml.drawing.endparagraphrunproperties.aspx
//Set the default formatting for words entered after "Hello World" with Font-Size 60x and Font-Color Blue.
A.EndParagraphRunProperties endParagraphRunProperties5 = new A.EndParagraphRunProperties() { Language = "en-US", FontSize = 6000, Dirty = false };//Set Font-Size to 60px.
A.SolidFill solidFill3 = new A.SolidFill();
A.RgbColorModelHex rgbColorModelHex3 = new A.RgbColorModelHex() { Val = "0070C0" };//Set Font-Color to Blue (Hex "0070C0").
solidFill3.Append(rgbColorModelHex3);
endParagraphRunProperties5.Append(solidFill3);

paragraph5.Append(run1);//Append Run: "Hello".
paragraph5.Append(run2);//Append Run: " World".
paragraph5.Append(endParagraphRunProperties5);//Append formmatting for any text the user may enter after the words "Hello World".
textBody5.Append(bodyProperties5);//Created but not modified.
textBody5.Append(listStyle5);//Created but not modified.
textBody5.Append(paragraph5);//Append Paragraph: "Hello World"

//TableCell Properties.  Set Background-Color to Red (Hex "FF0000").
A.TableCellProperties tableCellProperties3 = new A.TableCellProperties();
A.SolidFill solidFill4 = new A.SolidFill();
A.RgbColorModelHex rgbColorModelHex4 = new A.RgbColorModelHex() { Val = "FF0000" };//Red Background for Single TableCell.
solidFill4.Append(rgbColorModelHex4);
tableCellProperties3.Append(solidFill4);//Append Red Background.

tableCell3.Append(textBody5);
tableCell3.Append(tableCellProperties3);

I cheated and used the “Open XML SDK 2.0 Productivity Tool for Microsoft Office“.
I simply created a new PowerPoint file, added a table, and edited the 3rd Cell.
Then I ran the SDK tool and reflected the code on “[]/ppt/presentation.xml“.
I added comments to the reflected code so that you may understand it better.