c# - How can I make the SQL connect in a Windows Form? -


i'm still working on messenger programme, more secure i'm testing stuff. i've got login form meant connect sql database, i've set local sql trying working (it still doesn't work) , wondering did wrong.

private void button1_click(object sender, eventargs e)     {         logininfo.un = textbox1.text;         logininfo.pw = textbox2.text;          sqlconnection con = new sqlconnection();         con.connectionstring = "data source=localhost:3306; user id=pxgamer;password=password1; initial catalog=login;";         try         {             con.open();         }         catch (exception)         {             messagebox.show("error database connection");         }         string qry1 = "select * login password=@password , username=@username";         sqlcommand com = new sqlcommand(qry1, con);         com.parameters.addwithvalue("@username", logininfo.un);         com.parameters.addwithvalue("@password", logininfo.pw);         sqldatareader dr = com.executereader();         while (dr.read())         {             if (dr.hasrows == true)             {                 messagebox.show("login successful", "login information");             }         }         if (dr.hasrows == false)         {             messagebox.show("access denied", "login information");         }          this.hide();         var frmmain = new frmmain();         frmmain.closed += (s, args) => this.close();         frmmain.show();     }

so that's code, connection hangs @ first, , "error database connection" error appears. tried looking up, says it's when connection hasn't opened. i'm guessing it's wrong connection string.

in debugging, part gets highlighted:

sqldatareader dr = com.executereader();

this error shown:

an unhandled exception of type 'system.invalidoperationexception' occurred in system.data.dll

additional information: executereader requires open , available connection. connection's current state closed.

an unhandled exception of type 'system.data.sqlclient.sqlexception' occurred in system.data.dll

error without catch:

additional information: network-related or instance-specific error occurred while establishing connection sql server. server not found or not accessible. verify instance name correct , sql server configured allow remote connections. (provider: named pipes provider, error: 40 - not open connection sql server)

you trying connect mysql database using sql server-specific ado.net classes. won't work.

you can see current code trying connect sql server instance error message got:

additional information: network-related or instance-specific error occurred while establishing connection sql server. server not found or not accessible. verify instance name correct , sql server configured allow remote connections. (provider: named pipes provider, error: 40 - not open connection sql server)

you need download mysql-specific drivers connect mysql, , use instead.

ado.net driver mysql


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