c# - "Invalid operator for data type. Operator equals minus, type equals varchar." -

im trying make code checks table existing records same name receiving error "invalid operator data type. operator equals minus, type equals varchar." understand error dont understand why cant convert int.

this code, make work appreciated!

using system; using system.collections.generic; using system.linq; using system.web; using system.web.ui; using system.web.ui.webcontrols; using system.data.sqlclient; using system.configuration;   public partial class register : system.web.ui.page {     protected void page_load(object sender, eventargs e)     {          if (ispostback)         {             sqlconnection studconn = new sqlconnection(configurationmanager.connectionstrings["studconnectionstring"].connectionstring);             studconn.open();             string checkuser = "select count(*) studtable where-'" + textboxname.text + "'";             sqlcommand studcom = new sqlcommand(checkuser, studconn);             int temp = convert.toint32 (studcom.executescalar().tostring());             studconn.close();             if (temp == 1)             {                 response.write("user exists");             }          }        }       protected void button1_click(object sender, system.eventargs e)     {         try         {             guid studguid = guid.newguid();              sqlconnection studconn = new sqlconnection(configurationmanager.connectionstrings["studconnectionstring"].connectionstring);             studconn.open();             string insertquery = "insert studtable (id,name,email,age,continent,school,password) values (@id,@name,@email,@age,@cont,@school,@pass)";             sqlcommand studcom = new sqlcommand(insertquery, studconn);              studcom.parameters.addwithvalue("@id", studguid.tostring());             studcom.parameters.addwithvalue("@name", textboxname.text);             studcom.parameters.addwithvalue("@email", textboxemail.text);             studcom.parameters.addwithvalue("@age", textboxage.text);             studcom.parameters.addwithvalue("@cont", dropdowncont.selecteditem.tostring());             studcom.parameters.addwithvalue("@school", textboxschool.text);             studcom.parameters.addwithvalue("@pass", textboxpass.text);              studcom.executenonquery();             response.redirect("backend.aspx");             response.write("your registration sucessful");              studconn.close();         }         catch (exception ex)         {             response.write("error:" +ex.tostring());         }     } } 

thanks!

you need change command text , use parameterized queries instead of string concatenation

string checkuser = "select count(*) studtable name = @name"; sqlcommand studcom = new sqlcommand(checkuser, studconn); studcom.parameters.addwithvalue("@name", textboxname.text); 

you should remove (-) after where , use equality operator = check equality.