c# - How I can display message box when no result found in MS Access DB? -

how can display message box when no results found in ms access db using c#?

i'm using code search:

connection.open(); oledbcommand command = new oledbcommand(); command.connection = connection; string query = "select * emp emp_id '" + textbox5.text + "'"; command.commandtext = query; oledbdatareader reader = command.executereader(); while (reader.read()) {     slip.text = reader["emp_id"].tostring();  } connection.close();                 

you can use hasrows property.

gets value indicates whether oledbdatareader contains 1 or more rows.

if(reader.hasrows) {  } else {    // show message box here } 

also should use parameterized queries. kind of string concatenations open sql injection attacks.

and use using statement dispose oledbconnection, oledbcommand , oledbdatareader automatically instead of calling .close() or .dispose() methods manually.

using(var connection = new oledbconnection(constring)) using(var command = connection.createcommand()) {    command.commandtext = "select * emp emp_id ?";    command.parameters.addwithvalue("?", "%" + textbox5.text + "%");     using(var reader = command.executereader())    {        if(reader.hasrows)        {            while (reader.read())            {                 slip.text = reader["emp_id"].tostring();             }        }        else        {             // show message box here        }    } }