Loop through Textboxes

Question

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

DateTextBox0
DateTextBox1 ...
DateTextBox37

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?

Answer 1

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);
}

usage:

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

Answer 2

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){   
                textBoxes.add(c);   
        }   
    }   
return textBoxes;   
}

Answer 3

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)
           textBoxes.Add(box);
        if (c.Controls.Count > 0)
           textBoxes.AddRange(SearchTextBoxes(c.Controls));
    }

    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 :)