C# loop through an array of given labels

Question

It's a bit difficult for me to describe, but this pseudo C# should explain what I'm trying to do.

There is a large number of labels on a windows form.

I'd like to change the text colour of some of those labels.

private void allBlackLabels()
{
    int[] lray = { 1, 2, 3, 5, 6 };
    foreach (int i in lray)
    {
        label[i].Forecolor = Color.Black;
    }            
}

I hope that explains what I am trying to do here.

Now it's obvious it won't work due to the label[i], but how would I get around this?

Why is it "obvious it wont work due to the label[i]"? Should we assume you don't currently have your labels conveniently available? Is the real question here "how can I get all the labels from a form, keyed by their name in the form label17?" ? — Marc Gravell
– Marc Gravell, Commented Oct 17, 2011 at 9:26

Fischermaen · Accepted Answer · 2011-10-17 09:26:52Z

4

It might not work, because your Labels aren't held in an array. The following code will work, considering you know the names of the label to be changed:

Label[] lray = { labelOne, labelDifferent, labelWhatElse };
foreach (Label label in lray)
{
    label.ForeColor = Color.Black;
}

answered Oct 17, 2011 at 9:26

Fischermaen

12.5k2 gold badges43 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

tripbrock Over a year ago

This is perfect thank you! Why I was going down the route I was I will never know! Thank you sir.

Jon Skeet · Accepted Answer · 2011-10-17 09:25:15Z

1

That would work fine if you actually had an array of labels.

If you've only got lots of variables, like this:

private Label label1;
private Label label2;
private Label label3;
private Label label4;
private Label label5;

then it's harder. Options:

Change the code to use an array instead. Not as nice in the designer, but more logical
Use Controls.Find with each ID
Iterate over Controls to find all Label controls, regardless of name

answered Oct 17, 2011 at 9:25

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Comments

Kristian Fenn · Accepted Answer · 2011-10-17 09:25:16Z

1

foreach (Control c in this.Controls)
{
    if (c is Label)
    {
        // do stuff
    }
}

That'll grab all of the form's child controls (provided this code is in the form's code-behind) and check to see if they're labels. Just do any manipulation you want in place of the comment.

answered Oct 17, 2011 at 9:25

Kristian Fenn

8675 silver badges14 bronze badges

2 Comments

Jon Skeet Over a year ago

Personally I'd use LINQ there: foreach (Label label in this.Controls.OfType<Label>())

Fischermaen Over a year ago

But that will change all labels and tripbrock wanted to change only some of them.

jv42 · Accepted Answer · 2011-10-17 09:24:59Z

0

You could create the array yourself. This involves a bit of maintenance cost/risk each time your form changes though. Note: you probably want to put the array creation bit in a Form Loaded event, not a constructor, or at least, after the InitializeComponent call, so your controls are setup.

Or you could iterate on all the children of your Form (this.Controls from a Form method), mark your labels with a specific Tag, or get all Labels if that's your purpose here.

Please note that the first solution is probably much faster in runtime performance terms if you have many controls in your form.

answered Oct 17, 2011 at 9:24

jv42

8,5935 gold badges43 silver badges65 bronze badges

2 Comments

Kristian Fenn Over a year ago

If you give the labels the same name in the designer it'll create an array for you - no real chance of getting it wrong then. EDIT: Well, at least you used to be able to.

jv42 Over a year ago

@KristianFenn Interesting. That may or may not cover the use cases of OP though. For instance, he might have two different sets of labels depending on some runtime property.

John Gathogo · Accepted Answer · 2011-10-17 09:25:35Z

0

private void allBlackLabels()
{
    int[] lray = { 1, 2, 3, 5, 6 };
    foreach (int i = 0; i < lray.Length; i++)
    {
        ((Label)this.Controls["label" + i]).ForeColor = Color.Black;
    }            
}

answered Oct 17, 2011 at 9:25

John Gathogo

4,6753 gold badges36 silver badges50 bronze badges

Comments

Joey Ciechanowicz · Accepted Answer · 2011-10-17 09:29:24Z

0

If you want to achieve this for all labels on the form then something like this may help:

foreach (Control control in this.Controls) {
     if (control is Label) {
         (control as Label).Forecolor = Color.Black;
     }
}

However if you only need to change a subset of all the labels then you need to either store the names or the indexes of the labels which need changing. This is because this.Controls has two indexers, an int32 and a string one. Thus you could try something like this

private void allBlackLabels()
{
    int[] lray = { 1, 2, 3, 5, 6 };
    foreach (int i in lray)
    {
         this.Controls[i].Forecolor = Color.Black;
    }            
}

It is defiantly worth noting however that the ordering in this.Controls will most likely not be as liniear looking as your lray array. Hope this helps

answered Oct 17, 2011 at 9:29

Joey Ciechanowicz

3,6733 gold badges30 silver badges49 bronze badges

1 Comment

Marc Gravell Over a year ago

Let's hope all the controls are directly on the outermost control/form, and not-nested...

MoonKnight · Accepted Answer · 2011-10-17 09:35:11Z

0

Try some thing like this:

List<string> ListLabelNames = new List<string>() { /* Your label name list*/ };

foreach (Label TmpLabel in this.Controls.OfType<Label>())
{
    foreach (string strTmp in ListLabelNames)
    {
        if (String.Compare(TmpLabel.Name, strTmp, true) == 0)
            TmpLabel.ForeColor = System.Drawing.Color.Black;
    }
}

Hope this helps.

edited Oct 17, 2011 at 9:35

answered Oct 17, 2011 at 9:29

MoonKnight

23.9k42 gold badges154 silver badges284 bronze badges

Comments

CoderMike · Accepted Answer · 2014-12-23 05:52:40Z

0

I noticed that you excluded 4 from the "lray" array in your example. If you are looking to exclude one or more labels from being automatically updated by code (perhaps to highlight one among a group), try this.

    private void allBlackLabels()
    {    
        foreach (Control control in this.Controls)            
        {
            if (control is Label && control.Name != "label4")
            {
                (control as Label).Forecolor = Color.Black;
            }
        }
    }

answered Dec 23, 2014 at 5:52

CoderMike

214 bronze badges

Comments

Sam Holder · Accepted Answer · 2011-10-17 09:26:22Z

-1

in pseudo c#:

List<String> controlsToChange =new List<String>{"lable1Name","lable2Name"};
foreach(Control control in form.Controls)
{
    if(control.GetType().Equals(typeof(Lable))
    {
         if( controlsToChange.Contains(control.Name)
         {
              control.Forecolor=Colour.Black;
         }
    }
}

answered Oct 17, 2011 at 9:26

Sam Holder

33.1k14 gold badges108 silver badges190 bronze badges

6 Comments

Fischermaen Over a year ago

But that will change all labels and tripbrock wanted to change only some of them.

Sam Holder Over a year ago

@Fischermaen, really? or will it change only those which have entries in the controlsToChange list?

MoonKnight Over a year ago

No it will change only the labels specified in the List.

Fischermaen Over a year ago

@SamHolder: You're right. Sorry! If you have a List<Label> than you could save the test of the right type.

Sam Holder Over a year ago

@Fischermaen indeed your are right, you could save the test. Can you remove the downvote perhaps?

|

Collectives™ on Stack Overflow

C# loop through an array of given labels

9 Answers 9

1 Comment

Comments

2 Comments

2 Comments

Comments

1 Comment

Comments

Comments

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

9 Answers 9

1 Comment

Comments

2 Comments

2 Comments

Comments

1 Comment

Comments

Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related