asp.net - Calling a stored procedure with varchar as output parameter -

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• ado.net - size property has invalid size of 0 7 answers

i want assign output parameter of stored procedure session variable.so,basically,i looking call stored procedure has varchar out parameter.the stored procedure follows:

    alter proc spchecktaskperformed     @taskid int,     @email varchar(100),     @status varchar(100) output         begin     select @status = status tbltaskperformed     [email] = @email , [taskid]=@taskid     end 

the code have below:

      private void checktaskperformed() {     string cs = configurationmanager.connectionstrings["easyrozmoney_connectionstring"].connectionstring;     using (sqlconnection con = new sqlconnection(cs))     {         con.open();         sqlcommand cmd = new sqlcommand("spchecktaskperformed", con);         cmd.commandtype = commandtype.storedprocedure;         cmd.parameters.addwithvalue("@taskid", lbltaskid.text);         cmd.parameters.addwithvalue("@email", session["email"].tostring());          sqlparameter outputparameter = new sqlparameter();         outputparameter.parametername = "@status";         outputparameter.sqldbtype = system.data.sqldbtype.varchar;         outputparameter.direction = system.data.parameterdirection.output;         cmd.parameters.add(outputparameter);          cmd.executenonquery();          string status = outputparameter.value.tostring();         lblstatus.text = "this task has " + status;     } } 

but error message - string[2]: size property has invalid size of 0. @ below line.

    cmd.executenonquery(); 

you must send value status or specify null input:

 @status varchar(100) = null output