使用未分配的局部变量

Question

当我尝试调试此代码(在C#WinForms中)时,它显示错误

"使用未分配的局部变量"在'arrlist [i]'

由于我将它与数据库变量进行比较,我无法初始化数组的大小.

这是代码:

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]);
            }
       }
   }
}

请帮我

Answer 1

您需要初始化变量arrlist.改变这一行:

string[] arrlist;

对此:

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

或者更好的是,使用动态大小的容器,例如List<string>.

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

或者使用LINQ直接获得结果:

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