Data Reader error c#

Question

If type value non bar code active is line 49 and no have problems multiple times... Whene coplue times wrong bar code value I have error line 25 on code If is bar code from database ok working fine, if is bar code not ok firs time is ok, if wronf two times bar code errorr... Error is INVALID ATTEMP TO READ WHEN NO DATA IS PRESENT private void prijavaAction() { SqlConnection con = new SqlConnection(cs); if (textBox1.Text.All( char .IsDigit)) { string queryString = "SELECT [ime_prezime] FROM dbo.radnici WHERE bar_kod = '" + textBox1.Text + "'" ; using (SqlConnection connection = new SqlConnection(cs)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { if (reader.Read()) { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#2EFF36" ); messageLabel.Text = (reader[ "ime_prezime" ].ToString()) + " je prijavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); readerresultTextbox.Text = (reader[ "ime_prezime" ].ToString()); } else { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FD7400" ); messageLabel.Text = "Radnik ne postoji u bazi! 
Proverite vašu karticu ili probajte ponovo!" ; textBox1.Text = "" ; } } finally { if (reader.Read()) { //Insert into } else { //update } reader.Close(); } } } else { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FD7400" ); messageLabel.Text = "Bar kod nije važeci ili nije bar kod" ; textBox1.Text = "" ; } }

Rafnas T P · Answer

private void prijavaAction() { SqlConnection con = new SqlConnection(cs); if (textBox1.Text.All( char .IsDigit)) { string queryString = "SELECT [ime_prezime] FROM dbo.radnici WHERE bar_kod = '" + textBox1.Text + "'" ; // pronaci radnika u bazi using (SqlConnection connection = new SqlConnection(cs)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { if (reader.Read()) //radi //while (reader.Read()) //radi { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#2EFF36" ); messageLabel.Text = (reader[ "ime_prezime" ].ToString()) + " je prijavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); readerresultTextbox.Text = (reader[ "ime_prezime" ].ToString()); } else { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FD7400" ); messageLabel.Text = "Radnik ne postoji u bazi! 
Proverite vašu karticu ili probajte ponovo!" ; textBox1.Text = "" ; } } finally { string prijava = "SELECT count(*) from dbo.prijava_radnika where vrijemeprijave is not null and vrijemeodjave is null and radnik = '" + readerresultTextbox.Text + "' and redni_broj is NULL" ; SqlCommand provjeraprijaveradnika = new SqlCommand(prijava, con); con.Open(); int result = Convert.ToInt32(provjeraprijaveradnika.ExecuteScalar()); //con.Open(); con.Close(); if ((result == 0)) //radi //if ((prijava !)) { String saveStaff = "INSERT INTO dbo.prijava_radnika (vrijemeprijave, status, radnik,idfakture) VALUES(@vrijemeprijave,'prijavljen', '" + readerresultTextbox.Text + "',@idfakture)" ; using (SqlConnection openCon2 = new SqlConnection(cs)) { using (SqlCommand querySaveStaff = new SqlCommand(saveStaff)) { querySaveStaff.Connection = openCon2; querySaveStaff.Parameters.Add( "@vrijemeprijave" , SqlDbType.DateTime).Value = DateTime.Now; querySaveStaff.Parameters.Add( "@idfakture" , SqlDbType.Int).Value = id_fakture; openCon2.Open(); querySaveStaff.ExecuteNonQuery(); openCon2.Close(); //notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#FFE11A"); // messageLabel.Text = (reader["ime_prezime"].ToString()) + " je prijavljen u 
 " + DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss"); } } } else { String updateStaff = " declare @maxNo integer = 0 select @maxNo = isnull(max(redni_broj), 0) from[dbo].[prijava_radnika] UPDATE[dbo].[prijava_radnika] SET" + " [vrijemeodjave] = @vrijemeodjave,[redni_broj] = (@maxNo+1),[status] = 'odjavljen' WHERE radnik = '" + readerresultTextbox.Text + "'and[status] = 'prijavljen'" ; using (SqlConnection openCon3 = new SqlConnection(cs)) { using (SqlCommand queryupdateStaff = new SqlCommand(updateStaff)) { queryupdateStaff.Connection = openCon3; queryupdateStaff.Parameters.Add( "@vrijemeodjave" , SqlDbType.DateTime).Value = DateTime.Now; openCon3.Open(); queryupdateStaff.ExecuteNonQuery(); openCon3.Close(); } } string queryString = "SELECT [ime_prezime] FROM dbo.radnici WHERE bar_kod = '" + textBox1.Text + "'" ; // pronaci radnika u bazi using (SqlConnection connection = new SqlConnection(cs)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { if (reader.Read()) { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FFE11A" ); messageLabel.Text = (reader[ "ime_prezime" ].ToString()) + " je odjavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); } } catch { } } // Always call Close when done reading. reader.Close(); } } } } else { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FD7400" ); messageLabel.Text = "Bar kod nije važeci ili nije bar kod" ; textBox1.Text = "" ; } }

Goran Bibic · Answer

hi, you have to remove line 19 to line 24 full of else bolck (else{} 19,20,21,22,23,24 remove) Removeed...first time ok...another time same error

Rafnas T P · Answer

When you use while you have to remove else block

Goran Bibic · Answer

Insert while instead if on line 13 and I have error line 18...expeted }

Rafnas T P · Answer

if you wanted to fetch more data rows then use while (reader.Read()) instead of if (reader.Read())

Rafnas T P · Answer

hi, try below link https://stackoverflow.com/questions/1147615/invalid-attempt-to-read-when-no-data-is-present?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

Rafnas T P · Answer

what is the problem now

Rafnas T P · Answer

line no 66 to 77 that is the below code cut that using (SqlConnection openCon3 = new SqlConnection(cs)) { using (SqlCommand queryupdateStaff = new SqlCommand(updateStaff)) { queryupdateStaff.Connection = openCon3; queryupdateStaff.Parameters.Add( "@vrijemeodjave" , SqlDbType.DateTime).Value = DateTime.Now; openCon3.Open(); queryupdateStaff.ExecuteNonQuery(); openCon3.Close(); } } and past it into inside if(reader1.read()) that is after line 88

Goran Bibic · Answer

Error is: When put insert into sql work fine, deliberately put couple wrong codes...and try right code app must then work update...butt app automaticly work update when I put wrong code. I want when reader read to do insert or update...when is worng code to do nothing...some litle mistake

Goran Bibic · Answer

Working fine. Have some simple error... When I put some right code, app working if ((result == 0)) //radi { String saveStaff = "INSERT INTO dbo.prijava_radnika (vrijemeprijave, status, radnik,idfakture) VALUES(@vrijemeprijave,'prijavljen', '" + readerresultTextbox.Text + "',@idfakture)" ; That is ok... else work update fine...errorr is on next reply String updateStaff = " declare @maxNo integer = 0 select @maxNo = isnull(max(redni_broj), 0) from[dbo].[prijava_radnika] UPDATE[dbo].[prijava_radnika] SET" + " [vrijemeodjave] = @vrijemeodjave,[redni_broj] = (@maxNo+1),[status] = 'odjavljen' WHERE radnik = '" + readerresultTextbox.Text + "'and[status] = 'prijavljen'" ;

Rafnas T P · Answer

remove line no 79,80,81,82,83,84,85,86,87,89,90,91,92,93,and 94 and write below code or just rename red one as below using (SqlConnection connection1 = new SqlConnection(cs)) { SqlCommand command1 = new SqlCommand(queryString, connection1); nection1.Open(); SqlDataReader reader1 = command1.ExecuteReader(); try { if (reader1.Read()) { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FFE11A" ); messageLabel.Text = (reader1[ "ime_prezime" ].ToString()) + " je odjavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); } } catch { } }

Rafnas T P · Answer

remove line no 79 to 94 and write below code there if (reader.Read()) { notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FFE11A" ); messageLabel.Text = (reader[ "ime_prezime" ].ToString()) + " je odjavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); }

Goran Bibic · Answer

Its alredy defined in line 8,9,10,11...look in code

Goran Bibic · Answer

Parameters in line 79,80,82,84 alredy defined

Rafnas T P · Answer

from line 76, I have changed some code pls try this, the problem is there also you have to check if(reader.Read())

Goran Bibic · Answer

Your recommendations?

Rafnas T P · Answer

in line 77 there is no reader like in line 16, you have to write same in line 77 also

Goran Bibic · Answer

Invalid attempt to read when no data is present. That is errorr...line 16 update code String updateStaff = " declare @maxNo integer = 0 select @maxNo = isnull(max(redni_broj), 0) from[dbo].[prijava_radnika] UPDATE[dbo].[prijava_radnika] SET" + " [vrijemeodjave] = @vrijemeodjave,[redni_broj] = (@maxNo+1),[status] = 'odjavljen' WHERE radnik = '" + readerresultTextbox.Text + "'and[status] = 'prijavljen'" ; using (SqlConnection openCon3 = new SqlConnection(cs)) { using (SqlCommand queryupdateStaff = new SqlCommand(updateStaff)) { queryupdateStaff.Connection = openCon3; queryupdateStaff.Parameters.Add( "@vrijemeodjave" , SqlDbType.DateTime).Value = DateTime.Now; openCon3.Open(); queryupdateStaff.ExecuteNonQuery(); openCon3.Close(); notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml( "#FFE11A" ); messageLabel.Text = (reader[ "ime_prezime" ].ToString()) + " je odjavljen u 
 " + DateTime.Now.ToString( "dd.MM.yyyy HH:mm:ss" ); } } }

Rafnas T P · Answer

what isthe error you are getting

Rafnas T P · Answer

hi, you have to remove line 19 to line 24 full of else bolck (else{} 19,20,21,22,23,24 remove)

Goran Bibic · Answer

Remove else block (lines 18,19 and 20). Now no have no one worker ...every time is text from line 22....Like no have users in table...and after two times wrong code same error

Goran Bibic · Answer

I try for 10 minutes

Goran Bibic · Answer

On your code line 25,26 after tha app must do nothing...but app insert empty row

Goran Bibic · Answer

Error is on Line 25, 26,27....is problem....when put digits...app work insert comand last resulttextbox or empty row if I put some letters going to line 103 and do nothing...thast working fine.

Goran Bibic · Answer

When put wrong code or just hit enter hi insert into empty row or last resulttextbox...I want when is error or wrong code...do nothing..

Goran Bibic · Answer

Solved NOW. Thank you