How to use variable names that are created in a loop and stored in List?

Question

I have a List object that gets automatically filled with the names of textboxes. Now I'd like to cycle through all these text boxes. How can I let C# know that the string-names in the List are actually TextBox objects with that string-name?

        List<string> txtOppsNames = new List<string>(); 
        for (int i = 1; i < numOpps; i++) 
        {
            txtOppsNames.Add("txtOpp" + i);
        }
        foreach (var txtName in txtOppsNames) 
        {
            if (txtName.Text != "")
            {
                // do stuff
            }
        }

The current code reads txtName as a string. I would like it to read as a TextBox.

Edit - the below code contains the solution for me.

        List<string> txtOppsNames = new List<string>();
        for (int i = 1; i < numOpps; i++) 
        {
            txtOppsNames.Add("txtOpp" + i);
        }
        foreach (var txtName in txtOppsNames)
        {
            TextBox textBox = this.Controls.Find(txtName, true).FirstOrDefault() as TextBox;
            if (textBox.Text != "")
            {
                MessageBox.Show("Thanks Amir Popovich");
            }

        }

You can't do that, what environment are you working in? ASP.NET / Windows Forms etc. — Nunners, Nov 05 '14 at 07:33
`txtOppsNames` is a `List`. Why do you think your `txtName` can be a `TextBox`? — Soner Gönül, Nov 05 '14 at 07:35
You could consider creating the textboxes dynamically (not via designer), and add them to a `List` instead. — C.Evenhuis, Nov 05 '14 at 07:37
I'm using Windows Forms application. I'm used to doing similar operations in VBA-code, I'd love to use it in this environment. — Paretozen, Nov 05 '14 at 07:38
What are you trying to do with the text? and how are you filling the list? its possible that you could use data-binding or just use a `TextBox` list as previously suggested to achieve the same goal. — Sayse, Nov 05 '14 at 07:43
@Paretozen - two things: 1. change `if (textBox.Text != "")` to `if(textBox != null && textBox.Text != string.Empty)` since you are using `FirstOrDefault`. 2. You don't need to edit your question and add the answer- You need to accept the correct answer. — Amir Popovich, Nov 05 '14 at 08:29

Amir Popovich · Answer 1 · 2014-11-05T09:09:09.650

1

Use Control.ControlCollection.Find:

string textBoxName = "txtOpp1";
TextBox textBox = this.Controls.Find(textBoxName, true).FirstOrDefault() as TextBox;

In your case:

List<string> txtOppsNames = new List<string>(); 
for (int i = 1; i < numOpps; i++) 
{
    txtOppsNames.Add("txtOpp" + i);
}
foreach (var txtName in txtOppsNames) 
{
   var control = this.Controls.Find(txtName, true).FirstOrDefault();
   if(control != null && control is TextBox)
   {
      TextBox textBox = control as TextBox;
      if(textBox.Text != string.Empty)
      {
          //logic
      }
   } 
 }

edited Nov 05 '14 at 09:09

answered Nov 05 '14 at 07:34

Amir Popovich

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1

I like @Royi's answer, as it has the test to ensure it is a textbox, but I also like your `textBox.Text !=string.Empty.` – jbutler483 Nov 05 '14 at 08:57

score 1 · Answer 2 · answered Nov 05 '14 at 07:34

Try this :

  List<string> txtOppsNames = new List<string>(); 
        for (int i = 1; i < numOpps; i++) 
        {
            txtOppsNames.Add("txtOpp" + i);
        }
        foreach (var txtName in txtOppsNames) 
        {
          var cntrl= FindControl(txtName);
           if (cntrl!=null && cntrl is TextBox)
              // do something with 
              ((TextBox)cntrl)
       }

score 0 · Answer 3 · edited May 23 '17 at 12:05

0

Assuming it is Winform, There seems to be no pretty way to do it.

But you could use Loop through Textboxes.

once you have the text box collection, check the names with your string.

edited May 23 '17 at 12:05

Community

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answered Nov 05 '14 at 07:39

Ricky

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1

How to use variable names that are created in a loop and stored in List?

3 Answers3