Question

I want to put some numbers from Excel to array.
Let’s say I have an Excel file with some numbers like this:

23
34
1
3
100
56
45
43
56
4
87
6
89
9

this is just one column in excel (or any file)
And i want to put those numers in arraylist as integer numbers, i dont need the result as one number but all those numbers to be in int value.

Any help please ?

Answer 1

Assuming that the above is a string (and the source does not matter), you can do the following:

string s = "23 34 1 3 100 56 45 43 56 4 87 6 89 9";
string[] numbers = s.Split(' ');

ArrayList numberList = new ArrayList();
int i;

foreach (String num in numbers)
{
    if (Int32.TryParse(num, out i))
        numberList.Add(i);
    else
        Console.WriteLine("'{0}' is not a number!", num);
}

listBox1.DataSource = numberList;

I suggest using List<int> instead of ArrayList for type safety.

The following code reads all values from an Excel sheet into a data set using a DB connection. You can then pick the value needed.:

String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + filename + ";" + "Extended Properties=\"Excel 8.0;HDR=NO;IMEX=1ReadOnly=False\"";

OleDbConnection objConn = new OleDbConnection(sConnectionString);

objConn.Open();
OleDbCommand objCmdSelect = new OleDbCommand("SELECT * FROM [" + sheetname + "$]", objConn);

OleDbDataAdapter objAdapter1 = new OleDbDataAdapter();
objAdapter1.SelectCommand = objCmdSelect;

DataSet dsExcelContent = new DataSet();
objAdapter1.Fill(dsExcelContent);

objConn.Close();

EDIT
You did not specify the exact source for the string, so if this question is about how to read a file or how to import data from an Excel spreadsheet, you should probably rephrase your question a little.

EDIT 2
Replaced List<int> by ArrayList on OP’s wish (against better design).

EDIT 3
Added a new line to show the OP how to use the ArrayList as a data source for a ListBox…

EDIT 4
Added code to read Excel sheet using OleDB.