Array IndexOutOfRange

Question

        string temp = textBox1.Text;
        char[] array1 = temp.ToCharArray();
        string temp2 = "" + array1[0];
        string temp3 = "" + array1[1];
        string temp4 = "" + array1[2];
        textBox2.Text = temp2;
        textBox3.Text = temp3;
        textBox4.Text = temp4;

How do I prevent an IndexOutOfRange Error occurring when a user inputs less than three letters in textBox1?

You should check out temp's length (temp.Length) and see it it's above three, otherwise show an error or do nothing. — Raz Harush
– Raz Harush, Commented Jul 18, 2013 at 16:18
Can we assume textBox3.Text = temp4; this "3" is a typo and not an error and should be "4"? — Mark Schultheiss
– Mark Schultheiss, Commented Jul 18, 2013 at 16:24

Mark Schultheiss · Accepted Answer · 2013-07-18 16:28:39Z

10

How i will prevent IndexOutOfRange Error if a user only input less than three letters in the textBox1?

Just check that using temp.Length:

if (temp.Length > 0)
{
    ...
}

... or use switch/case.

Also, you don't need the array at all. Just call ToString on each character, or use Substring:

string temp = textBox1.Text;
switch (temp.Length)
{
    case 0:
        textBox2.Text = "";
        textBox3.Text = "";
        textBox4.Text = "";
        break;
    case 1:
        // Via the indexer...
        textBox2.Text = temp[0].ToString();
        textBox3.Text = "";
        textBox4.Text = "";
        break;
    case 2:
        // Via Substring
        textBox2.Text = temp.Substring(0, 1);
        textBox3.Text = temp.Substring(1, 1);
        textBox4.Text = "";
        break;
    default:
        textBox2.Text = temp.Substring(0, 1);
        textBox3.Text = temp.Substring(1, 1);
        textBox4.Text = temp.Substring(2, 1);
        break;
}

Another option - even neater - is to use the conditional operator:

string temp = textBox1.Text;
textBox2.Text = temp.Length < 1 ? "" : temp.Substring(0, 1);
textBox3.Text = temp.Length < 2 ? "" : temp.Substring(1, 1);
textBox4.Text = temp.Length < 3 ? "" : temp.Substring(2, 1);

edited Jul 18, 2013 at 16:28

Mark Schultheiss

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answered Jul 18, 2013 at 16:17

Jon Skeet

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1 Comment

Jon Skeet Over a year ago

@doctorlove: No, because I'm assuming that as many characters as possible should be filled - see my edits.

David R Tribble · Accepted Answer · 2013-07-18 16:23:08Z

0

A general solution to this kind of problem is to check the length of the source value (array, string, or vector) before accessing its elements. For example:

string  temp = textBox1.Text;

if (temp.Length > 0)
    textBox2.Text = temp.Substring(0, 1);
if (temp.Length > 1)
    textBox3.Text = temp.Substring(1, 1);
if (temp.Length > 2)
    textBox4.Text = temp.Substring(2, 1);

answered Jul 18, 2013 at 16:23

David R Tribble

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Comments

It'sNotALie. · Accepted Answer · 2013-07-18 16:26:26Z

0

Another way to do it is using ElementAtOrDefault:

    string[] temp = textBox1.Text.Select(c => c.ToString());
    string temp2 = "" + temp.ElementAtOrDefault(0);
    string temp3 = "" + temp.ElementAtOrDefault(1);
    string temp4 = "" + temp.ElementAtOrDefault(2);
    textBox2.Text = temp2;
    textBox3.Text = temp3;
    textBox3.Text = temp4;

edited Jul 18, 2013 at 16:26

answered Jul 18, 2013 at 16:20

It'sNotALie.

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2 Comments

cuongle Over a year ago

temp2 will be "\0" not string.Empty anymore

Jon Skeet Over a year ago

That will append a U+0000 when it's too short - it's not clear that that would be desirable.

Omkar Joshi · Accepted Answer · 2013-07-18 16:42:37Z

0

if the size is fixed i.e no. of character is 3 or length is 3 then it must be like .....

string temp = textBox1.Text; char[] array1 = temp.ToCharArray(); if(temp.length==3) { string temp2 = "" + array1[0]; string temp3 = "" + array1[1]; string temp4 = "" + array1[2]; textBox2.Text = temp2; textBox3.Text = temp3; textBox3.Text = temp4; } this will be work if u r string length is 3....

edited Jul 18, 2013 at 16:42

answered Jul 18, 2013 at 16:28

Omkar Joshi

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if the size is fixed i.e no. of character is 3 or length is 3 then it must be like .....

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if the size is fixed i.e no. of character is 3 or length is 3 then it must be like .....

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