Failed to convert parameter value from a String to

abhishekkashyap27 · November 28th, 2007, 05:51 AM

Hi All

I am just a novice in C# and got stuck on one point. I am using Javascript to validate my input in textbox1, The input has to be in numeric only. regular expression used in javascript is RE = new RegExp("[0-9]"). But when i am entering alphanumeric value, i am getting error as Failed to convert parameter value from a String to a Int32.

I am buiding a login page using duwamish architecture.

my access.cs code is:

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.OleDb;

namespace DataAccess
{
    public class Access
    {
        public bool LoginDetails(string struserid, string strpassword)
        {

            OleDbConnection conn = new OleDbConnection();
            conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
         @"Data source= C:\Documents and Settings\10082\" +
         @"My Documents\user.mdb";
            OleDbCommand cmd = new OleDbCommand("select Name,Department,Vertical,Location from user1 where userid=@userid and password=@password", conn);
            cmd.Parameters.Add("@userid", OleDbType.Integer, 10);
            cmd.Parameters["@userid"].Value = struserid;
            cmd.Parameters.Add("@password", OleDbType.WChar, 50);
            cmd.Parameters["@password"].Value = strpassword;
            conn.Open();
            OleDbDataReader reader = cmd.ExecuteReader();

            if (reader.HasRows)
                return true;
            else
                return false;

            //OleDbDataAdapter ad = new OleDbDataAdapter(cmd);
            //DataSet ds = new DataSet();
            //ad.Fill(ds, "user1");

            // Verify whether the user is existing from the returned dataset.

            // In case no user details exist with the provided credentials,
            //return false. Otherwise true.

        }

        public DataSet GetDetails(string struserid)
        {
            OleDbConnection conn = new OleDbConnection();
            conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
         @"Data source= C:\Documents and Settings\10082\" +
         @"My Documents\user.mdb";
            string strSelectQuery = "select Name,Department,Vertical,Location from user1 where userid=@userid";
            OleDbCommand cmd1 = new OleDbCommand(strSelectQuery, conn);
            cmd1.Parameters.Add("@userid", OleDbType.Integer, 10);
            cmd1.Parameters["@userid"].Value = struserid;
            //cmd.Parameters.Add("@password", OleDbType.WChar, 50);
            //cmd.Parameters["@password"].Value = strpassword;
            conn.Open();
            OleDbDataAdapter ad = new OleDbDataAdapter(cmd1);
            DataSet ds = new DataSet();
            ad.Fill(ds);
            return ds;

        }

    }
}

Please help....

joefawcett · November 28th, 2007, 06:24 AM

If you are sure your string only contains digits, and as you haven't shown the script that validates it's hard to tell, then try:

Code:

int myInt;
bool isInteger = int.TryParse(myString, out myInt);
if (isInteger)
{
  //myInt now holds legitimate value
}
else
{
  //error
}

--

Joe (Microsoft MVP - XML)

samjudson · November 28th, 2007, 06:27 AM

Your regular expression will only check that the input contains a single number, not that is consists only of numbers.

Try "^[0-9]+$" instead.

Obviously you should be doing the same check on the server as javascript may be turned off or bypassed on the client.

This is exactly what the Validation controls are for, as they can be confirmed on the server side as well (by checking Page.IsValid) while still providing client side feedback.

/- Sam Judson : Wrox Technical Editor -/