查看文本框是否为空C＃的最有效方法

Question

I have a webform that can have multiple text boxes.

Lets say 3: txt1 txt2 txt3

obviously I can write the following code:

bool atleastOneTextboxEmpty=false;

If (txt1.Text.Tostring().Trim()=="")
{
atleastOneTextboxEmpty=true;
}
If (txt2.Text.Tostring().Trim()=="")
{
atleastOneTextboxEmpty=true;
}
If (txt3.Text.Tostring().Trim()=="")
{
atleastOneTextboxEmpty=true;
}

But i'm pretty sure there is a better way to do this( but so far I was not able to find it).

Note: In my case I'm not allowed to use required field validators and form may have more textboxes which some of them are allowed to be empty(so I can't loop though all form textboxes).

Answer 1

Lambda way! First part Me.Controls.OfType(Of TextBox)() gets all the textboxes on the form, the Any function check a condition.

Dim anyEmptyTBs = Me.Controls.OfType(Of TextBox)().Any(Function(tb) String.IsNullOrWhiteSpace(tb.Text))

Answer 2

Create a collection/array of textboxes and then you can do:

var textBoxCollection = new[] { txt1, txt2, txt3 };

bool atleastOneTextboxEmpty = textBoxCollection
                                   .Any(t => String.IsNullOrWhiteSpace(t.Text));

The above will check all the textboxes in the array textBoxCollection and check if any one of them have empty/whitespace only value.

Use String.IsNullOrWhiteSpace instead of triming and than comparing value with empty string. Remember String.IsNullOrWhiteSpace is available with .Net framework 4.0 or higher.

---

Another option would be have these specific textboxes in a group control like Panel and then can use

yourPanel.Controls.OfType<TextBox>().Any(.....

Answer 3

You can write that simpler as:

bool atleastOneTextboxEmpty =
  txt1.Text.Trim() == "" ||
  txt2.Text.Trim() == "" ||
  txt3.Text.Trim() == "";

You can also put the controls in an array and check if any is empty:

bool atleastOneTextboxEmpty =
  new TextBox[] { txt1, txt2, txt3 }
  .Any(t => t.Text.Trim() == "");

Answer 4

You can use the Repeater control and define a TextBox inside its . In the code behind, do what you did but just make one if statement that chacks the textbox with the ID in the control