Pen.DashPattern Property

Definition

Namespace:

System.Drawing

Assembly:

System.Drawing.Common.dll

Source:

Pen.cs

Gets or sets an array of custom dashes and spaces.

C#

public float[] DashPattern { get; set; }

Property Value

Single[]

An array of real numbers that specifies the lengths of alternating dashes and spaces in dashed lines.

Exceptions

ArgumentException

The DashPattern property is set on an immutable Pen, such as those returned by the Pens class.

Examples

The following code example demonstrates the effects of setting the DashCap, DashPattern, and SmoothingMode properties.

This example is designed to be used with Windows Forms. Paste the code into a form and call the ShowPensAndSmoothingMode method when handling the form's Paint event, passing e as PaintEventArgs.

C#

private void ShowPensAndSmoothingMode(PaintEventArgs e)
{

    // Set the SmoothingMode property to smooth the line.
    e.Graphics.SmoothingMode = 
        System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

    // Create a new Pen object.
    Pen greenPen = new Pen(Color.Green);

    // Set the width to 6.
    greenPen.Width = 6.0F;

    // Set the DashCap to round.
    greenPen.DashCap = System.Drawing.Drawing2D.DashCap.Round;

    // Create a custom dash pattern.
    greenPen.DashPattern = new float[]{4.0F, 2.0F, 1.0F, 3.0F};

    // Draw a line.
    e.Graphics.DrawLine(greenPen, 20.0F, 20.0F, 100.0F, 240.0F);

    // Change the SmoothingMode to none.
    e.Graphics.SmoothingMode = 
        System.Drawing.Drawing2D.SmoothingMode.None;

    // Draw another line.
    e.Graphics.DrawLine(greenPen, 100.0F, 240.0F, 160.0F, 20.0F);

    // Dispose of the custom pen.
    greenPen.Dispose();
}

Remarks

Assigning a value other than null to this property will set the DashStyle property for this Pen to Custom.

The elements in the dashArray array set the length of each dash and space in the dash pattern. The first element sets the length of a dash, the second element sets the length of a space, the third element sets the length of a dash, and so on. Consequently, each element should be a non-zero positive number.

The length of each dash and space in the dash pattern is the product of the element value in the array and the width of the Pen.

Applies to