C#winfrom database additions and deletions to verify the case--sql operation version

Using system;using system.collections.generic;using system.componentmodel;using system.data;using System.Drawing; Using system.linq;using system.text;using system.windows.forms;using system.data.oledb;using System.Configuration; namespace testdboper{public partial class Fmmain:form {static string connstr = Configurationmanager.conne ctionstrings["ConnStr"].        ConnectionString;        Static Dbstate dbs;        Enum Dbstate {sadd, Smod, Sdel, Sbro} public Fmmain () {InitializeComponent (); private void Form1_Load (object sender, EventArgs e) {this.dataGridView1.AutoGenerateColumns = False        Do not automatically generate column Btnquery_click (sender, E); private void Btnexit_click (object sender, EventArgs e) {this.        Close ();            }//query private void Btnquery_click (object sender, EventArgs e) {int p = 0;         if (This.dataGridView1.CurrentCell! = null)   {p = this.dataGridView1.CurrentCell.RowIndex;            } OleDbConnection conn = new OleDbConnection (CONNSTR); OleDbDataAdapter da = new OleDbDataAdapter ("SELECT * from the users where username like '%" + this.textBox1.Text + "% '", conn)            ;            DataTable dt = new DataTable (); Conn.            Open (); Da.            Fill (DT);            This.dataGridView1.DataSource = DT; if (P < dataGridView1.Rows.Count) {This.dataGridView1.CurrentCell = Datagridview1.rows[p]. Cells[0]; } toolstripstatuslabel1.text = "Total query to" + dt.            Rows.Count.ToString () + "bar data";            DBS = Dbstate.sbro;        SETBTN ();            }//Added private void btnAdd_Click (object sender, EventArgs e) {dbs = Dbstate.sadd;            SETBTN ();        Usertxtclear ();            }//Modify private void Btnmod_click (object sender, EventArgs e) {dbs = Dbstate.smod;            SETBTN (); UserrefResh (); }//delete private void Btndel_click (object sender, EventArgs e) {if (MessageBox.Show ("You are sure you want to delete In addition to it?            "," hint ", messageboxbuttons.yesno)! = Dialogresult.yes) {return;}            String sql = "Delete from users where ID [email protected]";            OleDbConnection conn = new OleDbConnection (CONNSTR);            OleDbCommand cmd = new OleDbCommand (SQL, conn); oledbparameter[] param = {new OleDbParameter ("@id", This.datagridview1.rows[this.datagridview1.currentcell.rowindex ]. cells["id"].            Value.tostring ())}; Cmd.            Parameters.addrange (param); Conn.            Open ();            int n = 0; n = cmd.            ExecuteNonQuery (); Conn.            Close ();            if (n! = 0) {MessageBox.Show ("delete succeeded");            } else {MessageBox.Show ("delete failed");        } btnquery_click (sender, E); }//Save private void Btnsave_click (object sender,EventArgs e) {if (TxtUserName.Text.Trim () = = "") {MessageBox.Show ("name cannot be empty");                            Return                } if (TxtUserSex.Text.Trim () = = "") {MessageBox.Show ("Gender cannot be null");             Return                } if (TxtUserAge.Text.Trim () = = "") {MessageBox.Show ("Age cannot be empty");            Return } if (dbs = = dbstate.sadd) {String sql = "INSERT INTO Users (username,userage,userse                x) VALUES (@username, @userage, @usersex) ";                OleDbConnection conn = new OleDbConnection (CONNSTR);                OleDbCommand cmd = new OleDbCommand (SQL, conn); oledbparameter[] param ={New OleDbParameter ("@username", txtUsername.Text), new OLE DB    Parameter ("@userage", Txtuserage.text), New OleDbParameter ("@usersex", Txtusersex.text)                                 }; Cmd.                Parameters.addrange (param); Conn.                Open ();                int n = 0; n = cmd.                ExecuteNonQuery (); Conn.                Close ();                if (n! = 0) {MessageBox.Show ("add success");                } else {MessageBox.Show ("Increase failed"); }} else if (dbs = = dbstate.smod) {String sql = "Update users set [email&                Nbsp;protected],[email protected],[email protected] where id= @id ";                OleDbConnection conn = new OleDbConnection (CONNSTR);                OleDbCommand cmd = new OleDbCommand (SQL, conn); oledbparameter[] param ={New OleDbParameter ("@username", txtUsername.Text), new O Ledbparameter ("@userage", Txtuserage.text), New OleDbParameter ("@usersex", txtusers EX.text), New OleDbParameter ("@id", This.datagridview1.rows[datagridview1.currentce ll. RowIndex]. cells["id"].                Value.tostring ())}; Cmd.                Parameters.addrange (param); Conn.                Open ();                int n = 0; n = cmd.                ExecuteNonQuery (); Conn.                Close ();                if (n! = 0) {MessageBox.Show ("modified successfully");                } else {MessageBox.Show ("failed to modify");            }} dbs = Dbstate.sbro;            SETBTN ();        Btnquery_click (sender, E);            }//Cancels private void Btncancel_click (object sender, EventArgs e) {dbs = Dbstate.sbro;        SETBTN (); }//----------------------------------------------function------------------------------------------------//clear Empty input box private void usertxtclear ()       {txtusername.text = "";            Txtusersex.text = "";        Txtuserage.text = ""; }//Refresh user private void Userrefresh () {txtUsername.Text = This.datagridview1.rows[datagridv Iew1. Currentcell.rowindex]. cells["username"].            Value.tostring (); Txtusersex.text = This.datagridview1.rows[datagridview1.currentcell.rowindex]. cells["Usersex"].            Value.tostring (); Txtuserage.text = This.datagridview1.rows[datagridview1.currentcell.rowindex]. cells["Userage"].        Value.tostring ();            }//Set button state private void Setbtn () {btnadd.enabled = dbs = = Dbstate.sbro;            btnmod.enabled = DBS = = Dbstate.sbro;            btndel.enabled = DBS = = Dbstate.sbro;            btnquery.enabled = DBS = = Dbstate.sbro;            btnsave.enabled = dbs! = Dbstate.sbro;        btncancel.enabled = dbs! = Dbstate.sbro;     private void Datagridview1_doubleclick (object sender, EventArgs e)   {Btnmod_click (sender, E); }    }}

C#winfrom database additions and deletions to verify the case--sql operation version