Use of unassigned local variable

Question

While I am trying to debug this code (in C# WinForms), it shows an error

"use of unassigned local variable" at 'arrlist[i]'

Since I'm comparing it with a database variable, I cannot initialize the size of the array.

This is the code:

if (count != 0)
{
    OleDbCommand cmd1 = new OleDbCommand(
        "select seat_no, booking_date, show_time "+
        "from tickets "+
        "where ticket_no = (select max(ticket_no) from tickets)", c);
    OleDbDataReader oledb1 = cmd1.ExecuteReader();
    oledb1.Read();
    string retr_seats = oledb1.GetString(0);
    char comma = ',';
    string[] strarray = retr_seats.Split(comma);
    int ticket_length = strarray.Length;
    string[] arrlist;
    int i = 0;      
    foreach(var control in this.Controls)
    {
        if(control is Label)
        {           
            arrlist[i] = control.ToString();
            i++;
        }
   }       
   for(var j=0;j<=ticket_length;j++)
   {
       for (var k = 0; k <= i-1; k++)
       {
            if (arrlist[k].Contains(strarray[j]))
            {
                MessageBox.Show(strarray[j]);
            }
       }
   }
}

Please help me

Looks like you could just put string[] arrList = new arrList[this.Controls.Count]. — benjer3
– benjer3, Commented Jul 1, 2012 at 16:02
Actually, why not just have string[] arrList = this.Controls.Select(x => x.ToString()).ToArray();? — benjer3
– benjer3, Commented Jul 1, 2012 at 16:04
Possible duplicate of Why C# local variables must be initialized? — user12031933
– user12031933, Commented Nov 12, 2019 at 8:16

Mark Byers · Accepted Answer · 2012-07-01 16:32:08Z

8

You need to initialize the variable arrlist. Change this line:

string[] arrlist;

To this:

string[] arrlist = new string[this.Controls.Count]; // Must be big enough.

Or better, use a dynamically sized container such as a List<string>.

List<string> arrList = new List<string>();
foreach(var control in this.Controls)
{
    if(control is Label)
    {
        arrlist.Add(control.ToString());
    }
}

Or use LINQ to get the result directly:

string[] arrlist = this.Controls
    .OfType<Label>()
    .Select(control => control.ToString())
    .ToArray();

edited Jul 1, 2012 at 16:32

answered Jul 1, 2012 at 16:00

Mark Byers

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3 Comments

Mohan Raj K Over a year ago

But length is not there. only Count.. any way it works... Thanks for the help!! :)

Mark Byers Over a year ago

@MohanRajK: Thanks for the correction. Please also consider the other options because they are better.

Mohan Raj K Over a year ago

Do you upvote my question?? I'm in urgent that I want to ask another question with image. But I don't have enough reputation points. Please.. I want one more point

Monroe Thomas · Accepted Answer · 2012-07-01 16:09:24Z

1

Change your array to a list, and add values to the list. You can then index the list elements directly, or if you need an array, you can use .ToArray() on the list instance.

Also note that your for loop over j will go out of bounds on strarray unless you change the comparison to < ticket_length from <= ticket_length.

...

var arrlist = new List<string>();

foreach(var control in this.Controls) 
if(control is Label) 
{ 
    arrlist.Add(control.ToString()); 
} 

for(var j=0;j<ticket_length;j++)  
    for (var k = 0; k < arrlist.Count; k++)  
        if (arrlist[k].Contains(strarray[j]))  
             MessageBox.Show(strarray[j]);

answered Jul 1, 2012 at 16:09

Monroe Thomas

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Comments

burning_LEGION · Accepted Answer · 2012-07-01 16:02:23Z

0

string[] arrlist; .... arrlist[i] = control.ToString();

you lost initialization like: arrlist = new string[count];

answered Jul 1, 2012 at 16:02

burning_LEGION

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Comments

Tibi · Accepted Answer · 2012-07-01 16:02:31Z

0

The problem is that arrlist is defined, but not initialized.

You need to initialize it, like this:

string[] arrlist = new arrlist[size];

If you don't know how big it will be, it is better to use a list:

List<string> arrlist = new List<string>();

and to add items: arrlist.add("some string");

answered Jul 1, 2012 at 16:02

Tibi

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