Question

               ArrayList fileList = new ArrayList();


      private void button2_Click(object sender, EventArgs e)
            {
          if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
            string line;

            // Read the file and display it line by line.
            System.IO.StreamReader file = new System.IO.StreamReader(openFileDialog1.FileName);
            while ((line = file.ReadLine()) != null)
            {
                // Puts elements in table
                fileList.Add(line.Split(';'));
            }

            file.Close();
        }

        for (int i = 0; i < fileList.Count; i++)
        {
            for (int x = 0; x < (fileList[i] as string[]).Length; x++)
            {
               // if (x ==0)
              //  { 
                    //fileList[0] must Be int 
              //  }
               // if (x==1)
                    //fileList[1] must be string 

                this.textBox2.Text += ((fileList[i] as string[])[x] + " ");
            }

            this.textBox2.Text += Environment.NewLine;
        }
    }

I am so far here.

I take the elements from a CSV file.

I need now to be sure that the 1 column has only numbers-integers (1,2,3,4,5), the second column has only names(so it will have the type string or character), the third surnames etc. etc.

The rows are presented like this : 1;George;Mano;

How can I be sure that the CSV file has the correct types?

I think that any more code about this problem will be placed inside the 2 for statements.

Thank you very much,

George.

Answer 1

Edit: Now that we know it’s really CSV, here’s a columnar answer 😉

Your ArrayList contains string[], so you need to verify that each array has the appropriate type of string.

for (int i = 0; i < fileList.Count; i++)
{
   string[] lineItems = (string[])fileList[i];
   if (!Regex.IsMatch (lineItems[0], "^\d+$")) // numbers
      throw new ArgumentException ("invalid id at row " + i);
   if (!Regex.IsMatch (lineItems[1], "^[a-zA-Z]+$")) // surnames - letters-only
      throw new ArgumentException ("invalid surname at row " + i);
   if (!Regex.IsMatch (lineItems[2], "^[a-zA-Z]+$")) // names - letters-only
      throw new ArgumentException ("invalid name at row " + i);
}