Develop Reference

C# display components based on name

Is it possible to set a components visible attribute based on its name?
I have 12 "master" components (comboboxes) if you want to call them that and based on the selection in these I want to display anywhere from 1 to 16 textboxes. These are named in numeric order such as combobox1_textbox_0, combobox1_textbox_1 and so on. What I would like to do ideally is take the index of the combobox and pass it as a parameter to a method that sets the textboxes visible attribute to visible/hidden depending on the index passed into the method.
Is this possible? in pseudocode or what you call it I would like it to work something like this:
private void methodToSetVisibleAttribute(int indexFromMainComboBox)
{
for(int i = 0; i < 15; i++)
{
if(i < index)
{
combobox1_textbox_+i.Visible = true;
}
else
{
combobox1_textbox_+i.Visible = false;
}
}
}
I could do panels or something for the choices but seeing as all the selections from the combobox will use the same textboxes but in different amounts it seems like alot of work to make a panel for every possible selection not to mention difficult to expand the program later on.

Assuming you are using Windows Forms and not WPF, you can use ControlCollection.Find() to find controls by name:
var textBox = this.Controls.Find(string.Format("combobox1_textbox_{0}", i), true).OfType<ComboBox>().FirstOrDefault();
if (textBox != null)
textBox.Visible = (i < index);
else
Debug.Assert(false, "textbox not found"); // Or throw an exception if you prefer.

I'll suggest an alternative to your approach, maybe not quite what you're looking for:
Place your combo boxes in a List<ComboBox> and you can access them by an index number.
List<ComboBox> myCombos = new List<ComboBox>();
for (int i = 0; i < 16; i++)
{
ComboBox cb = new ComboBox();
//do what ever you need to do here. Set its location, add items, etc.
Form1.Controls.Add(cb); //Alternatively add it to another container.
myCombos.Add(cb); //Now it's in a list.
}
Modify them like this:
for(int i = 0; i < 15; i++)
{
if(i < index)
{
myCombos[i].Visible = true;
}
else
{
myCombos[i].Visible = false;
}
}
Or even more succintly:
for(int i = 0; i < 15; i++)
{
myCombos[i].Visible = i < index;
}

How to write to a dynamical number of Textboxes?

I have a form (Windows Forms) with dynamically created textboxes:
TextBox[] tbxCantServ = new TextBox[1];
int i;
for (i = 0; i < tbxCantServ.Length; i++)
{
tbxCantServ[i] = new TextBox();
}
foreach (TextBox tbxActualCant in tbxCantServ)
{
tbxActualCant.Location = new Point(iHorizontal, iVertical);
tbxActualCant.Name = "tbx" + counter++;
tbxActualCant.Visible = true;
tbxActualCant.Width = 44;
tbxActualCant.MaxLength = 4;
this.Controls.Add(tbxActualCant);
}
Now I want to fill them with data, how could I do that?
If I created some textboxes dynamically with the names:
"tbxActualServ.Name = "txt" + counter;"
How can I write in them? How can I access to them?
For example, if I have created tbx1, tbx2 and tbx3, I would have a "for" that fills tbx1.Text with "1", tbx2.Text with "2", and tbx3.Text with "3".
something like
"for from i=0 to counter {
tbx[i] = i
}"
of like:
this.Controls.OfType<TextBox>().Where(r => r.Name == "tbx" + counter).¿¿Write??(r => r.Text = i).ToString();
Thanks!

You could do something like this:
this.Controls.OfType<TextBox>().ToList<TextBox>().ForEach(tb => tb.Text = "bla bla");

Evening,
Guessing from your tags that this is a web forms project.. Im going to have to make some other assumptions.
I am guessing that you are creating your text boxes in code, something like
TextBox tb1 = new TextBox();
form1.Controls.Add(tb1);
TextBox tb2 = new TextBox();
form1.Controls.Add(tb2);
If this is the case then I believe that you could do something like this:
for (int i = 0; i < 2; i++)
{
TextBox tb1 = page.findControl("tb" + i.ToString());
tb1.Text = "This is number " + i.ToString();
}
There is another alternative, you could keep a collection of the controls as you create them, you could then iterate over the collection.
To be honest, without more details about your code it will be difficult to give a full answer, I think that this answers what you are looking for, if not update your question with more details and more of the code (the code where you are dynamically creating the controls would be useful)

While it's possible to access controls by their names (the way you do it depends on the technology - are you using WinForms, WPF, Web Forms, ...?), using an array of controls is a much better solution. Here's some pseudo-C#:
MyControl[] controls = new MyControl[length];
for(int n = 0; n < controls.Length; n++)
{
controls[n] = new MyControl(...);
}
// ...
for(int n = 0; n < controls.Length; n++)
{
DoSomethingWith( controls[n] );
}

How do I find and use a programatically-created control?

I've created a number of buttons on a form based on database entries, and they work just fine. Here's the code for creating them. As you can see I've given them a tag:
for (int i = 0; i <= count && i < 3; i++)
{
btnAdd.Text = dataTable.Rows[i]["deviceDescription"].ToString();
btnAdd.Location = new Point(x, y);
btnAdd.Tag = i;
this.Controls.Add(btnAdd);
}
I use these buttons for visualising a polling system. For example, I want the button to be green when everything is fine, and red when something is wrong.
So the problem I'm running into is referencing the buttons later so that I can change their properties. I've tried stuff like the following:
this.Invoke((MethodInvoker)delegate
{
// txtOutput1.Text = (result[4] == 0x00 ? "HIGH" : "LOW"); // runs on UI thread
Button foundButton = (Button)Controls.Find(buttonNumber.ToString(), true)[0];
if (result[4] == 0x00)
{
foundButton.BackColor = Color.Green;
}
else
{
foundButton.BackColor = Color.Red;
}
});
But to no avail... I've tried changing around the syntax of Controls.Find() but still have had no luck. Has anyone encountered this problem before or know what to do?

If you name your buttons when you create them then you can find them from the this.controls(...
like this
for (int i = 0; i <= count && i < 3; i++)
{
Button btnAdd = new Button();
btnAdd.Name="btn"+i;
btnAdd.Text = dataTable.Rows[i]["deviceDescription"].ToString();
btnAdd.Location = new Point(x, y);
btnAdd.Tag = i;
this.Controls.Add(btnAdd);
}
then you can find it like this
this.Controls["btn1"].Text="New Text";
or
for (int i = 0; i <= count && i < 3; i++)
{
//**EDIT** I added some exception catching here
if (this.Controls.ContainsKey("btn"+buttonNumber))
MessageBox.Show("btn"+buttonNumber + " Does not exist");
else
this.Controls["btn"+i].Text="I am Button "+i;
}

Put these buttons in a collection and also set the name of the Control rather than using its tag.
var myButtons = new List<Button>();
var btnAdd = new Button();
btnAdd.Text = dataTable.Rows[i]["deviceDescription"].ToString();
btnAdd.Location = new Point(x, y);
btnAdd.Name = i;
myButtons.Add(btnAdd);
To find the button use it.
Button foundButton = myButtons.Where(s => s.Name == buttonNumber.ToString());
Or Simply
Button foundButton = myButtons[buttonNumber];

In your case I would use a simple Dictionary to store and retrieve the buttons.
declaration:
IDictionary<int, Button> kpiButtons = new Dictionary<int, Button>();
usage:
Button btnFound = kpiButtons[i];

#Asif is right, but if you really want to utilize tag you can use next
var button = (from c in Controls.OfType<Button>()
where (c.Tag is int) && (int)c.Tag == buttonNumber
select c).FirstOrDefault();
I'd rather create small helper class with number, button reference and logic and keep collection of it on the form.

C# - Assign values to controls thought loop

I have controls that are named in numeric sequence.
I'd like to assign values those controls using loop.
The code below is the way i'm currently using.
txtSalesInvoiceForm_Qty1.Text = (salesInvoice.ItemQty1 == 0) ? string.Empty : salesInvoice.ItemQty1.ToString();
txtSalesInvoiceForm_Qty2.Text = (salesInvoice.ItemQty2 == 0) ? string.Empty : salesInvoice.ItemQty2.ToString();
txtSalesInvoiceForm_Qty3.Text = (salesInvoice.ItemQty3 == 0) ? string.Empty : salesInvoice.ItemQty3.ToString();
txtSalesInvoiceForm_Qty4.Text = (salesInvoice.ItemQty4 == 0) ? string.Empty : salesInvoice.ItemQty4.ToString();
txtSalesInvoiceForm_Qty5.Text = (salesInvoice.ItemQty5 == 0) ? string.Empty : salesInvoice.ItemQty5.ToString();
txtSalesInvoiceForm_Unit1.Text = salesInvoice.Unit1;
txtSalesInvoiceForm_Unit2.Text = salesInvoice.Unit2;
txtSalesInvoiceForm_Unit3.Text = salesInvoice.Unit3;
txtSalesInvoiceForm_Unit4.Text = salesInvoice.Unit4;
txtSalesInvoiceForm_Unit5.Text = salesInvoice.Unit5;
txtSalesInvoiceForm_Particulars1.Text = salesInvoice.Particulars1;
txtSalesInvoiceForm_Particulars2.Text = salesInvoice.Particulars2;
txtSalesInvoiceForm_Particulars3.Text = salesInvoice.Particulars3;
txtSalesInvoiceForm_Particulars4.Text = salesInvoice.Particulars4;
txtSalesInvoiceForm_Particulars5.Text = salesInvoice.Particulars5;
Is there any way something like this?
int index = 1;
foreach (SalesInvoiceItem item in salesInvoice.SalesInvoiceItems)
{
(txtSalesInvoiceForm_Qty + index.ToString()).Text = Value;
indexer++
}

Control parent = this.pnlParent; // this must be the immediate parent control
int index = 1;
foreach (SalesInvoiceItem item in salesInvoice.SalesInvoiceItems)
{
TextBox tb = parent.FindControl( "txtSalesInvoiceForm_Qty" + index++ ) as TextBox;
tb.Text = Value;
}
The key is FindControl(), which searches the immediate children of a parent. Personally I think this is sloppy code in most cases.

Use an array rather than so many named variables and just index into the array.

How to dynamically set a control using variables C#

How do you dynamically call a control and set it property at runtime?
// Declare and set queue servers
string[] queueservers = new string[] { "SERVER1", "SERVER2", "SERVER3", "SERVER4" };
int y;
for (y = 0; y <= queueservers.Length - 1; y++)
{
string queueanswer = GetMailQueueSize(queueservers[y]);
if (queueanswer == "alarm")
{
phxQueueImg + queueservers + .ImageUrl = "~/images/Small-Down.gif";
}
else
{
phxQueueImg + queueservers + .ImageUrl = "~/images/Small-Up.gif";
}
queueanswer = "";
}

See here about asking good questions .
I'm going to assume you pasted the wrong code since it doesn't seem to have anything to do with the question afaik. Plus could edit your question and tag if this is winform, wpf or web?
Here I dynamically create the control at runtime:
Textbox c = new Textbox();
Set its text, eg
string s = "Please paste code that relates to your question";
c.Text = s;
Or here I dynamically set my textbox controls property using variables:
propertyInfo = c.GetType().GetProperty(property);
if (propertyInfo != null)
{
propertyInfo.SetValue(c, value, null);
}

try FindControl("controlID") and then cast the result of this call to the required control type and set the needed property.
(SomeParentControl.FindControl("IDOfControlToFind") AS LinkButton).PostBackUrl = "~/someresource.aspx";