Question

I am in need of some help. I am building a custom web user control which is going to be picking colours.

As of right now, it has two [asp:textbox]es on the page (foregroundColour and backgroundColour).

I want my foreground colour to default to “FFFFFF” and my background colour to default to “000000”, AND I the user to be able to specify their own initial values though the tag.

<ucFontChooser id="testchooser" runat="server" foregroundcolor="AABBCC" />

I have two properties that are tied to the textboxes:

[DefaultValue("000000")]
public string ForegroundColor { get { return foregroundColorSelectorHex.Text; } set { foregroundColorSelectorHex.Text = value; } }
[DefaultValue("FFFFFF")]
public string BackgroundColor { get { return backgroundColorSelectorHex.Text; } set { backgroundColorSelectorHex.Text = value; } }

Please note that I am aware that the DefaultValue is only for the visual studio property window and doesn’t actually set any value.

However, I have tried to set the default value by in the constructor of the usercontrol to do:

ForegroundColor = "000000"

This gives me an exception, because at the point of the constructor, the foregroundColorSelectorHex is null.

So if I try and setting the default in the OnInit event, or on *Page_Load* then it simply always uses the default I set and the set property value of “AABBCC” is overwritten.

What is the correct way to do what am I trying?

Thank you.

Answer 1

After much debugging, I came up with a solution to do exactly what I need.

public override string ID
{
    set
    {
        base.ID = value;
        InitializeProperties();
    }
}

protected void InitializeProperties()
{
    ForegroundColor = "000000";
    BackgroundColor = "ffffff";
    EnableBackgroundColor = false;
    PrimaryFont = "Arial";
    SecondaryFont = "Helvetica";
    TertiaryFont = "sans-serif";
}

the .NET framework will call mycontrol.ID = “bla”, which is when the user controls subcontrols come into context. It is called BEFORE the containing control/page reads the tags attributes and sets the properties.

Looks hacky, but works great.