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ASPxCaptcha.ChallengeImageCustomRender Event

Enables you to implement custom logic for rendering the ASPxCaptcha’s challenge image.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v24.2.dll

NuGet Package: DevExpress.Web

#Declaration

public event ChallengeImageCustomRenderEventHandler ChallengeImageCustomRender

#Event Data

The ChallengeImageCustomRender event's data class is ChallengeImageCustomRenderEventArgs. The following properties provide information specific to this event:

Property Description
Code Gets the code generated within the challenge image of the ASPxCaptcha control.
Image Provides access to a Bitmap object representing the ASPxCaptcha’s challenge image.

#Remarks

The ChallengeImageCustomRender event occurs before each render of the challenge image.

The parameters of the event argument allow you to obtain the generated code (ChallengeImageCustomRenderEventArgs.Code) and draw a custom image (ChallengeImageCustomRenderEventArgs.Image).

#Example

The example below demonstrates how to handle the ChallengeImageCustomRender event to implement a custom challenge image.

<dx:ASPxCaptcha ID="ASPxCaptcha1" runat="server" 
                OnChallengeImageCustomRender="OnChallengeImageCustomRender" />
protected void OnChallengeImageCustomRender(object sender, ChallengeImageCustomRenderEventArgs e) {
    using (Graphics graphics = Graphics.FromImage(e.Image)) {
        System.Drawing.Image backgroundImage = System.Drawing.Image.FromFile(Server.MapPath("~/pp.jpg"));
        graphics.DrawImage(backgroundImage, 0, 0, e.Image.Width, e.Image.Height);
        Font font = new Font("Times New Roman", 40.0f, FontStyle.Bold, GraphicsUnit.Pixel);
        graphics.DrawString(e.Code, font, Brushes.Red, new PointF(0.0f, 0.0f));
        graphics.Flush();
    }
}

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See Also