Visual Basic 6 Black Book
(Publisher: The Coriolis Group)
Author(s): Steven Holzner
ISBN: 1576102831
Publication Date: 08/01/98

The Span Method

Besides the SelRTF property, you can use the Span() method to select text based on a set of characters:

RichTextBox.Span characterset, [forward, [negate]]

The characterset parameter is a string that specifies the set of characters to look for. The forward parameter determines which direction the insertion point moves. The negate parameter specifies whether the characters in characterset define the set of target characters or are excluded from the set of target characters.

You use Span() to extend a selection from the current insertion point based on a set of specified characters. This method searches the text in the rich text box (forwards or backwards as you’ve specified) and extends the text selection to include (or exclude, if you’ve so specified) as many of the characters you’ve specified in the character set that it can find. For example, to select the text from the current insertion point to the end of the sentence, use Span(“.?!”), which works for sentences ending in periods, question marks, or exclamation marks.

Here’s an example where we use Span() to find the word “underlined” and underline it:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold, _
        italic, and strikethru text."

    RichTextBox1.SelStart = RichTextBox1.Find("underlined")
    RichTextBox1.Span ("underlined")
    RichTextBox1.SelUnderline = True
End Sub

Using Bold, Italic, Underline, And Strikethru

To make text bold, italic, underlined, or strikethru, you use the SelBold, SelItalic, SelUnderline, and SelStrikethru properties. These properties work on selected RTF text only, so you have to select the text whose format you want to change.

To make this clearer, here’s an example where we set the underline, bold, italic, and strikethru properties of text. We start by placing some text into a rich text box:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold,_
        italic, and strikethru text."
...

Next, we’ll underline the word “underlined” in the text. We start by finding that word using the rich text box Find() method:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold,_
        italic, and strikethru text."

    RichTextBox1.SelStart = RichTextBox1.Find("underlined")
...

We then use Span() to select the word “underlined”:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold,_
        italic, and strikethru text."

    RichTextBox1.SelStart = RichTextBox1.Find("underlined")
    RichTextBox1.Span ("underlined")
...

Finally, we underline the selected text by setting the rich text box’s SelUnderline property to True:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold,_
        italic, and strikethru text."

    RichTextBox1.SelStart = RichTextBox1.Find("underlined")
    RichTextBox1.Span ("underlined")
    RichTextBox1.SelUnderline = True
...

And we can do the same to demonstrate bold, italic, and strikethru text:

Private Sub Command1_Click()
    RichTextBox1.Text = "This rich text box supports underlined, bold,_
        italic, and strikethru text."

    RichTextBox1.SelStart = RichTextBox1.Find("underlined")
    RichTextBox1.Span ("underlined")
    RichTextBox1.SelUnderline = True
    RichTextBox1.SelStart = 0
    RichTextBox1.SelStart = RichTextBox1.Find("bold")
    RichTextBox1.Span ("bold")
    RichTextBox1.SelBold = True

    RichTextBox1.SelStart = 0
    RichTextBox1.SelStart = RichTextBox1.Find("italic")
    RichTextBox1.Span ("italic")
    RichTextBox1.SelItalic = True

    RichTextBox1.SelStart = 0
    RichTextBox1.SelStart = RichTextBox1.Find("strikethru")
    RichTextBox1.Span ("strikethru")
    RichTextBox1.SelStrikeThru = True
End Sub

Running this program yields the results you see in Figure 6.9.

Figure 6.9  Setting rich text properties.

Indenting Text In Rich Text Boxes

One of the aspects of word processors that users have gotten used to is the ability to indent text, and rich text boxes (which are designed to be RTF word processors in a control) have this capability. To indent paragraph-by-paragraph, you use these properties (you set them to numeric values to indicate the indentation amount, using the measurement units of the underlying form, which is usually twips):

•  SelIndent—Indents the first line of the paragraph

•  SelHangingIndent—Indents all other lines of the paragraph with respect to SelIndent

•  SelRightIndent—Sets the right indentation of the paragraph

To use these properties on a paragraph of text, you either select the paragraph (using SelStart and SelLength, or Span()), or simply place the insertion point in the paragraph (you can move the insertion point under program control with the UpTo() method).

Here’s an example: When the user places the insertion point in a paragraph of text and clicks a button, Command1, we can indent the paragraph 500 twips. We can then outdent all lines after the first by 250 twips with respect to the overall 500-twip indentation (which means that all lines after the first will be indented 250 twips from the left margin) and set the right indent to 100 twips:

Private Sub Command1_Click()
    RichTextBox1.SelIndent = 500
    RichTextBox1.SelHangingIndent = -250
    RichTextBox1.SelRightIndent = 100
End Sub

Running this code on a paragraph of text yields the result you see in Figure 6.10. Now we’re indenting individual paragraphs in rich text controls.

Figure 6.10  Indenting a paragraph of text.

Besides working paragraph-by-paragraph, you can set the right margin for the whole rich text at once with the RightMargin property. Just assign this property the new value you want for the right margin, and you’re set.