Loop through Textboxes

I have a winforms app that has 37 textboxes on the screen. Each one is sequentially numbered:

DateTextBox1 ...

I am trying to iterate through the text boxes and assign a value to each one:

int month = MonthYearPicker.Value.Month;
int year = MonthYearPicker.Value.Year;
int numberOfDays = DateTime.DaysInMonth(year, month);

m_MonthStartDate = new DateTime(year, month, 1);
m_MonthEndDate = new DateTime(year, month, numberOfDays);

DayOfWeek monthStartDayOfWeek = m_MonthStartDate.DayOfWeek;
int daysOffset = Math.Abs(DayOfWeek.Sunday - monthStartDayOfWeek);

for (int i = 0; i <= (numberOfDays - 1); i++)
 //Here is where I want to loop through the textboxes and assign values based on the 'i' value
   DateTextBox(daysOffset + i) = m_MonthStartDate.AddDays(i).Day.ToString();

Let me clarify that these textboxes appear on separate panels (37 of them). So in order for me to loop through using a foreach, I have to loop through the primary controls (the panels), then loop through the controls on the panels. It starts getting complicated.

Any suggestions on how I can assign this value to the textbox?


To get all controls and sub-controls recursively of specified type, use this extension method:

public static IEnumerable<TControl> GetChildControls<TControl>(this Control control) where TControl : Control
    var children = (control.Controls != null) ? control.Controls.OfType<TControl>() : Enumerable.Empty<TControl>();
    return children.SelectMany(c => GetChildControls<TControl>(c)).Concat(children);


var allTextBoxes = this.GetChildControls<TextBox>();
foreach (TextBox tb in allTextBoxes)
    tb.Text = ...;

You Could loop all the controls in the form asking one by one if it is a "Textbox" y ther return the complete List of them.

public List GetTextBoxes(){   
    var textBoxes = new List();   
        foreach (Control c in Controls){   
            if(c is TextBox){   
return textBoxes;   

You can loop through the textboxes in your form in a fairly simple manner:

Func<ControlCollection, List<TextBox>> SearchTextBoxes = null;
SearchTextBoxes = coll => {
    List<TextBox> textBoxes = new List<TextBox>();

    foreach (Control c in coll) {
        TextBox box = c as TextBox;
        if (box != null)
        if (c.Controls.Count > 0)

    return textBoxes;

var tbs = SearchTextBoxes(this.Controls).OrderBy(tb => tb.Name);

Edit: Changed according to new requirements. Not nearly as elegant as the LINQ-solution, of course :)

Iterate through controls within form and check name of the control if matched then set Text property as you require.

int i = 0;
foreach (Control contrl in this.Controls) {
    if (contrl.Name == ("DateTextBox" + i.ToString())) {
        contrl.Text = "requiredtexttobeset";
    i = i + 1;

Since this post seems to resurrect itself from time to time and since the solutions above do not find controls inside of controls, such as in a groupbox, this will find them. Just add your control type:

    public static IList<T> GetAllControls<T>(Control control) where T : Control
        var lst = new List<T>();
        foreach (Control item in control.Controls)
            var ctr = item as T;
            if (ctr != null)

        return lst;

And it's use:

        var listBoxes = GetAllControls<ListBox>(this);
        foreach (ListBox lst in listBoxes)
            //Do Something

If you want to do without 'foreach' (If you have specific boxes to adjust/address)

int numControls = Page.Form.Controls.Count;

    for (int i = 0; i < numControls; i++)
        if (Page.Form.Controls[i] is TextBox)
            TextBox currBox = Page.Form.Controls[i] as TextBox;
            currbox.Text = currbox.TabIndex.ToString();

        //THE EASY WAY! Always post easy solutions. It's the best way.
        //This code is used to loop through all textboxes on a form for data validation. 
        //If an empty textbox is found, Set the error provider for the appropriate textbox.
        foreach (var control in Controls)
            if (control is TextBox)
                //Box the control into a textbox. Not really needed, but do it anyway
                var textbox = (TextBox)control;

                if (String.IsNullOrWhiteSpace(textbox.Text))
                    //Set the errorProvider for data validation
                    errorProvider1.SetError(textbox, "Data Required!");
                    textbox.Text = String.Empty; //Clear out the whitespace if necessary
                    //blnError = true;

You can simply do this mate...

foreach (TextBox txt in this.Panel.Controls.OfType<TextBox>())
                txt.Text="some value you assign";

If your text boxes are on the form directly and not on a Panel then you can replace this.Panel.Controls with this.Controls. That should be short and clear enough for you.

After the InitialiseComponents() call, add the textboxes to a collection member variable on the form. You can then iterate through them in order later on.

You can create a Dictionary of TextBox, int like the following

Dictionary<TextBox, int> textBoxes = new Dictionary<TextBox, int>();

foreach (TextBox control in Controls.OfType<TextBox>())
    textBoxes[control] = Convert.ToInt32(control.Name.Substring(11));

Now.. to loop through them..

foreach (var item in textBoxes.Select(p => new { textBox = p.Key, no = p.Value}))
     item.textBox.Text = item.no.ToString(); // whatever you want...

Good luck!

Since you already know the name of control, therefore you can search the control by its name.

See Get a Windows Forms control by name in C#

Other answers just not cutting it for you? I found this as an answer to a similar question on SO, but I can't find the thread now. It recursively loops through ALL controls of a given type which are located within a control. So includes children of children of children of... etc. My example changes the ForeColor of each TextBox to Hot Pink!

public IEnumerable<Control> GetAllControlsOfType(Control control, Type type)
    var controls = control.Controls.Cast<Control>();

    return controls.SelectMany(ctrl => GetAllControlsOfType(ctrl, type))
                              .Where(c => c.GetType() == type);


IEnumerable<Control> allTxtBxs = GetAllControlsOfType(this, typeof(TextBox));
foreach (TextBox txtBx in allTxtBxs)
    txtBx.ForeColor = Color.HotPink;

Quite similar to abatishchev's answer(which, for me, only returned first-level child controls), but different enough to merit it's own answer I think.

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