ASP.NET Password TextBox

dknyoli

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31 Mar 20071 min read

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A password textbox that survives postback and that can be set programmatically.

Download source code (demo project included) - 10.8 Kb

Introduction

Using ASP.NET, the default textbox in password mode (TextMode="Password") has the following restrictions:

The password can not be set (e.g., tbPassword.Text = "123";)
The password is not restored after a postback

Both restrictions make perfect sense for security reasons. Nonetheless, sometimes the above behaviour is not wanted (especially during development).

The new PasswordTextBox control is an extension of the standard ASP.NET TextBox and makes a password textbox behave like a regular textbox.

Using the code

The code itself is pretty straightforward:

public class PasswordTextBox : TextBox
{
    public PasswordTextBox()
    {
        TextMode = TextBoxMode.Password;
    }

    public override string Text
    {
        get
        {
            return base.Text;
        }
        set
        {
            base.Text = value;

            Attributes["value"] = value;
        }
    }

    protected override void OnPreRender(EventArgs e)
    {
        base.OnPreRender(e);

        Attributes["value"] = Text;
    }
}

To use the code, just drop PasswordTextBox.dll in the /bin of your web application, or add a reference to it in Visual Studio.

ASP.NET 2.0 offers a nice and clean way to register controls for your aspx pages: you simply add the following to your web.config:

XML

<pages>
    <controls>
        <add tagPrefix="opp" assembly="PasswordTextBox" namespace="opp"/>
    </controls>
</pages>

Now, you can use the PasswordTextBox as follows:

HTML

<opp:PasswordTextBox id="tbPassword" runat="server" />

Points of interest

To set the value of the PasswordTextBox, the Text property is overriden and the value is set via the "value" attribute.

To restore the value of PasswordTextBox after a postback, the value is retrieved in the OnPreRender event and set via the "value" attribute (thanks to jackmos for this more nifty solution).

History

V1.0 Released 2007-03-21.
V1.1 Released 2007-03-31. Thanks for all the good feedback!

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

Written By

dknyoli

Team Leader

Germany

Passionate about C#, .NET, SharePoint, iOS, Swift and Machine Learning.

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public class PasswordTextBox : TextBox { public PasswordTextBox() { } [DefaultValue(TextBoxMode.Password)] public override TextBoxMode TextMode { get { object value = this.ViewState["Mode"]; if (null != value) return (TextBoxMode)value; return TextBoxMode.Password; } set { if (!Enum.IsDefined(typeof(TextBoxMode), value)) { throw new ArgumentOutOfRangeException("value"); } this.ViewState["Mode"] = value; } } protected override void AddAttributesToRender(HtmlTextWriter writer) { base.AddAttributesToRender(writer); if (TextBoxMode.Password == this.TextMode) { writer.AddAttribute(HtmlTextWriterAttribute.Value, this.Text); } } }

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