query in asp.net language

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i have multiple sqlquery in page..so use sqlcommand object to fire query...so if i use cmd multiple times then it gives error that cmd already exist so i used cmd1,cmd2,cmd3 etc but it is not good way of coding so how can initialise sqlcommand object publically in top of page????
plz help me...
my code is below:-

C#

string mail = "select CONTACT_EMAIL from QAFranchise.HDR_CONTACT_LIST where CONTACT_EMAIL='"+Class1.MailID+"'";
        SqlCommand cmd5 = new SqlCommand(mail, cn);
        string mailid = Convert.ToString(cmd5.ExecuteScalar());

        string contactID = "select CONTACT_LIST_ID,CONTACT_EMAIL from QAFranchise.HDR_CONTACT_LIST where CONTACT_EMAIL='"+mailid+"' ";
        SqlCommand cmd6 = new SqlCommand(contactID, cn);
        Class1.ContactlistID = Convert.ToInt32(cmd6.ExecuteScalar());

thanks in advance.

[edit]code block added[/edit]

Posted 17-Nov-12 0:43am

Member 9027483

Updated 17-Nov-12 1:30am

Nelek

v2

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Dominic Abraham · Answer 1 · 2012-11-17T01:56:00

Hi
It is better and easy to use a separate class for the database operations. For Example.

C#

protected void Page_Load(object sender, EventArgs e)
   {
       dbConnection connection = new dbConnection();
       private void FetchContactMail()
       {
          string contactEmail = string.Empty;
          object myData = connection.FetchMyData("select CONTACT_EMAIL from QAFranchise.HDR_CONTACT_LIST where CONTACT_EMAIL = 'yourmail'");
          if (myData != null)
              contactEmail = myData.ToString();
       }
       private void FetchContactID()
       {
           int contactID = -1;
           object myData = connection.FetchMyData("select CONTACT_LIST_ID from QAFranchise.HDR_CONTACT_LIST where CONTACT_EMAIL = 'yourmail'");
           if (myData != null)
               contactID = Convert.ToInt32(myData);
       }
   }

And a new class for database operations.

C#

class dbConnection
{
    private string _connectionString = "your connection string";
    public object FetchMyData(string query)
    {
        object objVal;
        using (SqlConnection con = new SqlConnection(_connectionString))
        {
            con.Open();

            using(SqlCommand cmd = new SqlCommand(query,con))
            {
                objVal = cmd.ExecuteScalar();
            }
        }
        return objVal;

    }

}

Then it will be easier for you to manage.

mayankkarki · Answer 2 · 2012-11-17T01:21:00

Solution 1

Code like this

SqlCommand cmd=new SqlCommand();

cmd.CommandText="";
cmd.Connection=cn;
cmd.ExecuteScalar();

If you have parameters that clear them.
cmd.Parameters.Clear();

cmd.CommandText="";
cmd.executeScalar();

Ask me if you have any questions?

Posted 17-Nov-12 1:21am

mayankkarki