c# - Using String.Format when passing DateTime arguments type to DB. Exception is thrown. What is wrong? -

         object args = new object[] { "project", "projectname", "@prname", "projectstartdate", "@startdate", "projectenddate", "@enddate", "projectid", "@id" }; 

//******************this line causes exception thrown *******************

            string commandstring = string.format(@"update {0} set {1} = {2}, {3} = {4} , {5} = {6} {7} = {8}", args);              command.commandtext = commandstring;             command.commandtype = commandtype.text;             command.connection = connection;             command.parameters.add("@id", sqldbtype.int).value = selid;             command.parameters.add("@prname", sqldbtype.text).value = projectname;              command.parameters.add("@startdate", sqldbtype.datetime).value = startdate;             command.parameters.add("@enddate", sqldbtype.datetime).value = enddate;              connection.open();             int result = command.executenonquery(); 

// **************** exception details *****************************

system.formatexception unhandled message=index (zero based) must greater or equal 0 , less size of argument list. source=mscorlib stacktrace: @ system.text.stringbuilder.appendformat(iformatprovider provider, string format, object[] args)

   @ system.string.format(iformatprovider provider, string format, object[] args)     @ system.string.format(string format, object arg0)     @ dal.dataaccess.updaterec(int32 selid, string projectname, datetime startdate, datetime enddate) in \projects\consulting\dal\dataaccess.cs:line 106    @ consulting.frmproject.btnadd_click(object sender, eventargs e) in \frmproject.cs:line 48 

try below code. should work.

object[] args = new object[]   { "project", "projectname", "@prname", "projectstartdate", "@startdate", "projectenddate", "@enddate", "projectid", "@id" }; 

if works please mark answer.