need help

[mjawadkhatri]

Hi, this is my coding -------------------------------------------------------------------- while (odr.Read()) { if (usr.Text == odr["userid"].ToString()) { MessageBox.Show("User Login", "Information", MessageBoxButtons.OK); } else { DialogResult drsave = MessageBox.Show("Login Fail", "Erorr", MessageBoxButtons.OKCancel, MessageBoxIcon.Error); if (drsave == DialogResult.OK) { usr.Text = ""; pass.Text = ""; usr.Focus(); } else this.Close(); } } ------------------------------------------------------------------------ My program Build Successfully but when i type in textbox any string value my program read every value in my database in give every time message. for example in my database have 5 records my program read this records in give message 5 time :sigh: i want my program check all records in give one message record found or not please give me solution thanks in advanc jawad khatri i want to

[SeMartens]

Hi, it seems that you want to check if a user exists or not. I would seperate the presentation (your dialog) from the dataaccess (the select). Try to implement it like this:

private bool DoesUserExists(string sUserID) {
... perform a select statement here with a prepared statement
... then check if you have exactly one record
bool bResult = odr.Read(); --> true if you have one record
... close everything
return b;
}

public void CheckUser() {
... get the value from your textbox
// call method to check if user exists
if(this.DoesUserExists(sUserID)) {
// show success dialog
} else {
// show failure dialog
}
}

That would be a better approach than yours. By the way, it doesn't make any sense to check the userid in your database within the code, use the WHERE-clause of SELECT-statements for this. Hope this helps a bit. Regards Sebastian

It's not a bug, it's a feature! Check out my CodeProject article Permission-by-aspect. Me in Softwareland.

[K0306]

Try the below sample code query = "select username from tablename where username = '" + usr.text + "'"; sqlcommand cmd = new sqlcommand(query,con); sqldatareader dr; dr=cmd.executereader(); while(dr.read()) { if(dr["username"].tostring() == usr.text) { true user } else { false user } } dr.close();

Regards, Karthik K...

[mjawadkhatri]

Thank U For Reply Me bt How I perform Ur Coding In My Coding???? This is my All Coding In Button_click() --------------------------------------------------------------------------- using system; using Microsoft.data.odbc; private void login_Click(object sender, EventArgs e) { OdbcConnection cn; OdbcCommand cmd; OdbcDataReader odr; string MyString; MyString = "Select * from users"; cn = new OdbcConnection("Driver={Microsoft ODBC for Oracle};Server=orcl8i;UID=itehad;PWD=creative;"); cmd = new OdbcCommand(MyString, cn); cn.Open(); MessageBox.Show("Connected"); cmd.CommandText = "Select * from users"; odr = cmd.ExecuteReader(); while (odr.Read()) { if (usr.Text == odr["userid"].ToString()) { MessageBox.Show("User Login", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information); } else { DialogResult drsave = MessageBox.Show("Login Fail", "Erorr", MessageBoxButtons.OKCancel, MessageBoxIcon.Error); if (drsave == DialogResult.OK) { usr.Text = ""; pass.Text = ""; usr.Focus(); } else this.Close(); } } } --------------------------------------------------------------------------- Thanks In Advace Jawad Khatri

[N a v a n e e t h]

SeMartens wrote:

odr.Read(); --> true if you have one record

ExecuteScalar will be more appropriate in this case than reader.

Navaneeth How to use google | Ask smart questions

[SeMartens]

Okay, normally you should write it by yourself, but today is friday, so here it comes:

private bool DoesUserExists(string sUserID) {
OdbcConnection cn;
OdbcCommand cmd;
OdbcParameter dbParameter;
OdbcDataReader odr;

string MyString = "Select * from users WHERE userid = @userid";

cn = new OdbcConnection("Driver={Microsoft ODBC for Oracle};Server=orcl8i;UID=itehad;PWD=creative;");
cn.Open();
cmd = new OdbcCommand(MyString, cn);
dbParameter = new OdbcParameter("userid", sUserID");
cmd.Parameters.Add(dbParameter);
odr = cmd.ExecuteReader();

bool bResult = (odr.HasRows && odr.Read());
odr.Close();
cn.Close();
return bResult;

}

private void login_Click(object sender, EventArgs e)
{
if(this.DoesUserExists(usr.Text)) {
MessageBox.Show("User Login", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
} else {
DialogResult drsave = MessageBox.Show("Login Fail", "Erorr", MessageBoxButtons.OKCancel, MessageBoxIcon.Error);
if (drsave == DialogResult.OK)
{
usr.Text = "";
pass.Text = "";
usr.Focus();
} else {
this.Close();
}
}
}

You should add fail-safe to your app by using try-catch blocks, especially while interacting with the database. Next step would be to seperate the dataccess into an own assembly. Regards Sebastian

It's not a bug, it's a feature! Check out my CodeProject article Permission-by-aspect. Me in Softwareland.

[SeMartens]

Yep, you are right... but we want to confuse beginners, or? :)

It's not a bug, it's a feature! Check out my CodeProject article Permission-by-aspect. Me in Softwareland.

[Nagy Vilmos]

Be careful about how you test for equality, in all but the rarest case you shoud use the Equals method.

a == b

This compares two objects and returns true if they are they same object, that is the same instance. This does not compare the content.

a.Equals(b)

Compares the two instances and is defined by each classes implimentation. In the trivial case of the string, it returns true if they have the same content. Any class you write should override this method if you need to compare instances' values.

---

Panic, Chaos, Destruction. My work here is done.

[mjawadkhatri]

Thanks Alot Sir for Help me Sir When I Run this program give error Error Is Error 1 'Microsoft.Data.Odbc.OdbcDataReader' does not contain a definition for 'HasRows'

[mjawadkhatri]

sir Actually i am use dotnet after 1 year thats why i am facing lot of problem sir i kindly request to u please give me solution :sigh:

[SeMartens]

Why don't you use the System.Data.Odbc.OdbcDataReader?

It's not a bug, it's a feature! Check out my CodeProject article Permission-by-aspect. Me in Softwareland.

[mjawadkhatri]

ok. i use this and trying to solve my problem sorry for distrb u Sir:sigh:

[SeMartens]

No problem. And please don't call me sir... :) Just give a feedback if your problem is solved. Regards Sebastian

It's not a bug, it's a feature! Check out my CodeProject article Permission-by-aspect. Me in Softwareland.

[mjawadkhatri]

Thanks Again