How to Select particular text in textbox while textbox receives focus

问题

I am developing one ASP.NET application with VB code.I have one textbox to hold the amount, which contains default value as "0.00". Now the problem is while the textbox gets focus it selects all the text. But i want to select only 0 that is before precision and I do not want to select after precision.

Hope someone will help me. Thanks in advance

回答1:

assume you have TextInput you want to select its first character, whenever its selected

<input id="MyText" type="text" value="text" onclick="MyText_click()" />

and the script is like this:

<script>

    function MyText_click() {

        var input = document.getElementById("MyText");
        createSelection(input, 0, 1); // first character
    };

    function createSelection(field, start, end) {
        if (field.createTextRange) {
            var selRange = field.createTextRange();
            selRange.collapse(true);
            selRange.moveStart('character', start);
            selRange.moveEnd('character', end);
            selRange.select();
            field.focus();
        } else if (field.setSelectionRange) {
            field.focus();
            field.setSelectionRange(start, end);
        } else if (typeof field.selectionStart != 'undefined') {
            field.selectionStart = start;
            field.selectionEnd = end;
            field.focus();
        }
    }

</script>

回答2:

you can do that programmatically using javascript, see this: Programmatically selecting partial text in an input field

回答3:

Create event for text focus

Now we have two properties

   txt.SelectionStart = intValue

and

  txt.selectionLength = length;

Use this property to resolve your stuff

来源：https://stackoverflow.com/questions/21604919/how-to-select-particular-text-in-textbox-while-textbox-receives-focus