CharacterRange(Int32, Int32) Constructor

Definition

Namespace:

System.Drawing

Assembly:

System.Drawing.Common.dll

Initializes a new instance of the CharacterRange structure, specifying a range of character positions within a string.

public:
 CharacterRange(int First, int Length);

public CharacterRange (int First, int Length);

new System.Drawing.CharacterRange : int * int -> System.Drawing.CharacterRange

Public Sub New (First As Integer, Length As Integer)

Parameters

First

Int32

The position of the first character in the range. For example, if First is set to 0, the first position of the range is position 0 in the string.

Length

Int32

The number of positions in the range.

Examples

The following code example demonstrates how to create a CharacterRange and use it to highlight part of a string. This example is designed to be used with Windows Forms. Paste the example into a form and call the HighlightACharacterRange method when handling the form's Paint event, passing e as PaintEventArgs.

void HighlightACharacterRange( PaintEventArgs^ e )
{
   // Declare the string to draw.
   String^ message = "This is the string to highlight a word in.";

   // Declare the word to highlight.
   String^ searchWord = "string";

   // Create a CharacterRange array with the searchWord 
   // location and length.
   array<CharacterRange>^ temp = {CharacterRange( message->IndexOf( searchWord ), searchWord->Length )};
   array<CharacterRange>^ranges = temp;

   // Construct a StringFormat object.
   StringFormat^ stringFormat1 = gcnew StringFormat;

   // Set the ranges on the StringFormat object.
   stringFormat1->SetMeasurableCharacterRanges( ranges );

   // Declare the font to write the message in.
   System::Drawing::Font^ largeFont = gcnew System::Drawing::Font( FontFamily::GenericSansSerif,16.0F,GraphicsUnit::Pixel );

   // Construct a new Rectangle.
   Rectangle displayRectangle = Rectangle(20,20,200,100);

   // Convert the Rectangle to a RectangleF.
   RectangleF displayRectangleF = displayRectangle;

   // Get the Region to highlight by calling the 
   // MeasureCharacterRanges method.
   array<System::Drawing::Region^>^charRegion = e->Graphics->MeasureCharacterRanges( message, largeFont, displayRectangleF, stringFormat1 );

   // Draw the message string on the form.
   e->Graphics->DrawString( message, largeFont, Brushes::Blue, displayRectangleF );

   // Fill in the region using a semi-transparent color.
   e->Graphics->FillRegion( gcnew SolidBrush( Color::FromArgb( 50, Color::Fuchsia ) ), charRegion[ 0 ] );
   delete largeFont;
}

private void HighlightACharacterRange(PaintEventArgs e)
{

    // Declare the string to draw.
    string message = "This is the string to highlight a word in.";

    // Declare the word to highlight.
    string searchWord = "string";

    // Create a CharacterRange array with the searchWord 
    // location and length.
    CharacterRange[] ranges = 
        new CharacterRange[]{new CharacterRange
        (message.IndexOf(searchWord), searchWord.Length)};

    // Construct a StringFormat object.
    StringFormat stringFormat1 = new StringFormat();

    // Set the ranges on the StringFormat object.
    stringFormat1.SetMeasurableCharacterRanges(ranges);

    // Declare the font to write the message in.
    Font largeFont = new Font(FontFamily.GenericSansSerif, 16.0F,
        GraphicsUnit.Pixel);

    // Construct a new Rectangle.
    Rectangle displayRectangle = new Rectangle(20, 20, 200, 100);

    // Convert the Rectangle to a RectangleF.
    RectangleF displayRectangleF = (RectangleF)displayRectangle;

    // Get the Region to highlight by calling the 
    // MeasureCharacterRanges method.
    Region[] charRegion = e.Graphics.MeasureCharacterRanges(message, 
        largeFont, displayRectangleF, stringFormat1);

    // Draw the message string on the form.
    e.Graphics.DrawString(message, largeFont, Brushes.Blue, 
        displayRectangleF);

    // Fill in the region using a semi-transparent color.
    e.Graphics.FillRegion(new SolidBrush(Color.FromArgb(50, Color.Fuchsia)), 
        charRegion[0]);

    largeFont.Dispose();
}

Private Sub HighlightACharacterRange(ByVal e As PaintEventArgs)

    ' Declare the string to draw.
    Dim message As String = _
        "This is the string to highlight a word in."

    ' Declare the word to highlight.
    Dim searchWord As String = "string"

    ' Create a CharacterRange array with the searchWord 
    ' location and length.
    Dim ranges() As CharacterRange = _
        New CharacterRange() _
            {New CharacterRange(message.IndexOf(searchWord), _
            searchWord.Length)}

    ' Construct a StringFormat object.
    Dim stringFormat1 As New StringFormat

    ' Set the ranges on the StringFormat object.
    stringFormat1.SetMeasurableCharacterRanges(ranges)

    ' Declare the font to write the message in.
    Dim largeFont As Font = New Font(FontFamily.GenericSansSerif, _
        16.0F, GraphicsUnit.Pixel)

    ' Construct a new Rectangle.
    Dim displayRectangle As New Rectangle(20, 20, 200, 100)

    ' Convert the Rectangle to a RectangleF.
    Dim displayRectangleF As RectangleF = _
        RectangleF.op_Implicit(displayRectangle)

    ' Get the Region to highlight by calling the 
    ' MeasureCharacterRanges method.
    Dim charRegion() As Region = _
        e.Graphics.MeasureCharacterRanges(message, _
        largeFont, displayRectangleF, stringFormat1)

    ' Draw the message string on the form.
    e.Graphics.DrawString(message, largeFont, Brushes.Blue, _
        displayRectangleF)

    ' Fill in the region using a semi-transparent color.
    e.Graphics.FillRegion(New SolidBrush(Color.FromArgb(50, _
        Color.Fuchsia)), charRegion(0))

End Sub