C# .net winforms data insert error -

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.drawing; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms; using system.data.sqlclient;  namespace crudwithlogin {     public partial class student_registration : form     {         sqlconnection conn = new sqlconnection(@"data source=(localdb)\mssqllocaldb;attachdbfilename=c:\users\android\documents\data.mdf;integrated security=true;connect timeout=30");          public student_registration()         {             initializecomponent();         }          private void student_registration_load(object sender, eventargs e)         {             label1.text = "you logged in "+((form)this.mdiparent).controls["label1"].text;         }          private void button1_click(object sender, eventargs e)         {             conn.open();             sqlcommand cmd = conn.createcommand();             cmd.commandtype = commandtype.text;             cmd.commandtext = "insert student values ('"                                                     + textbox1.text                                                     + "','"                                                     + textbox2.text                                                     + "''"                                                     + datetimepicker2.value.tostring()                                                     + "','"                                                     + textbox4.text                                                     + "','"                                                     + combobox2.text                                                     + "','"                                                     + textbox6.text                                                     + "','"                                                     + datetimepicker1.value.tostring()                                                     + "')";             cmd.executenonquery();             conn.close();             messagebox.show("data added successfully. ");         }     } } 

hello experts creating windows forms app using c#, trying insert data database getting error of values , columns not match though entering right value right attribute.

i have 8 attributes (id auto increment), , remaining 7 columns entering 7 values error of value not match.

please me solve problem. have attached code , screenshots of problem

error shown here:

database schema screenshot here

('" + textbox1.text + "','" + textbox2.text + "''" + datetimepicker2.value.tostring() + "','"  //missed , ------------------------------------^ 

also use command.parameters in future , avoid problems ! protected sqlinjection. here example how define params.

 sqlcommand cmd = conn.createcommand();  cmd.commandtype = commandtype.text;  cmd.commandtext = @"insert tablenamefromdb values (@id, @title)";  cmd.parameters.addwithvalue("@id", youridvalue);  cmd.parameters.addwithvalue("@title", yourtitlevalue);  cmd.executenonquery();  conn.close(); 

also don't share 1 connection in app, use multiple connections. connection pool friend. check using block , use auto disposing of idisposable objects( example: sqlconnection).