Resetting Property to Default/empty

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2.00/5 (1 vote)

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Hello, I have an UserControl in my From Project,

I have this Code in the UserControl:

C#

public partial class iktMarquee : UserControl
{
    #region Properties
    private string _Text = "";//This parameter will change when changing property 'Text' in property manager in a form
    private int charIndex = 0;
    private Color _FontColor = Color.White;

    [Description("Sets Marquee Text"), DefaultValue(""), Category("Vales"), Browsable(true)]

    public string Text
    {
        get { return _Text; }
        set { _Text = value; }
    }

    [Description("Sets Marquee Font Color"), Category("Appearance"), DefaultValue("White"),  Browsable(true)]
    public Color FontColor
    {
        get { return _FontColor; }
        set { _FontColor = value; }
    }

    [Description("Sets Marquee Interval"), Category("Behavior"), DefaultValue(1000),  Browsable(true)]
    public int Interval
    {
        get { return ScrollTimer.Interval; }
        set { ScrollTimer.Interval = value; }
    }
    #endregion

    #region Control Start
    public iktMarquee()
    {
        InitializeComponent();

    }

    private void iktMarquee_Load(object sender, EventArgs e)
    {

    }
    #endregion

    #region Painting
    public void RePaint()
    {
        System.Drawing.Pen myPen;
        myPen = new System.Drawing.Pen(_FontColor);
        System.Drawing.Graphics formGraphics = this.CreateGraphics();
        formGraphics.Clear(this.BackColor);
        formGraphics.DrawString(_Text.Remove(0,charIndex), this.Font, new SolidBrush(this.FontColor), 5,5);
        myPen.Dispose();
        formGraphics.Dispose();

    }
    #endregion

    #region Private Functions
    private void ScrollTimer_Tick(object sender, EventArgs e)
    {
        //charIndex++;
        if (charIndex > _Text.Length)
            charIndex = 0;
        RePaint();
    }

    private void iktMarquee_Resize(object sender, EventArgs e)
    {
        RePaint();
    }
    #endregion

    private void iktMarquee_Paint(object sender, PaintEventArgs e)
    {
        RePaint();
    }
}

Then I have built the project, then set the 'Text' value in UserControl to 'Teststring '

When I Start in debug mode, the 'Text' gets reset to '', while it should be 'Teststring'.

How can I fix this?

Thanks!

Edit:
Posted full code of UserControl

Posted 7-Feb-12 10:10am

ikkentim

Updated 7-Feb-12 10:54am

v2

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Comments

Sergey Alexandrovich Kryukov 7-Feb-12 16:47pm

Why your code sample is broken at this point? Could you fix it?
--SA

ikkentim 7-Feb-12 17:08pm

posted full code

2 solutions

Solution 1

There is no a concept of "default property value" in .NET, because it is hardly needed as an universal concept.

You should introduce such behavior on the level of your particular class. Just add and implement some methods like Reset(), SetThisToDefault(), ResetThat() or anything like that to your liking.

Now, your problem is different: you code sample is incomplete, so I cannot tell where is the problem, but right now I can see only the Text getter, and not setter. If there is no setter, or a setter is private, you have no a way to assign a value to the property, it will always remain an empty string.

Another flaw (which does not compromise functionality but really bad for maintenance): never hard-code and immediate constants, especially strings, except null, of course. In particular, never write "", always use string.Empty. The default value is null.

—SA

Posted 7-Feb-12 10:45am

Sergey Alexandrovich Kryukov

Updated 7-Feb-12 10:46am

v2

Comments

ikkentim 7-Feb-12 17:08pm

How I need to make that setter? Isn't ... set { _Text = value; } ... right then?

DaveyM69 7-Feb-12 17:26pm

All properties have a default value, the value depends on the type. In general, for value types it is 0 or the type's equivalent, for reference types it is null.

In the case of user controls, the default value can be set using the DefaultValue attribute, and a TypeConverter if one is needed.

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DaveyM69 · Accepted Answer · 2012-02-07T11:22:00

The user control already has a text property, it's just hidden. Override and decorate with the correct attributes and you can use it without any added fields etc:

C#

[Bindable(true),
Browsable(true),
DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
EditorBrowsable(EditorBrowsableState.Always)]
public override string Text
{
    get { return base.Text; }
    set { base.Text = value; }
}