c# - Input string was not in a correct format in my gridview -

here, have attendance table having attributes such

status - bit,  studid - bigint (foreign key),  attendanceid - int =>primary key , identity(true)  

and student table having

studid - bigint =>primary key,  studfirstname - varchar(50),  studlastname - varchar(50)  

to displayed in gridview. here code :

using system; using system.collections.generic; using system.linq; using system.web; using system.web.ui; using system.web.ui.webcontrols;  public partial class class_content_addattendancesss : system.web.ui.page { dataclassesdatacontext db = new dataclassesdatacontext(); protected void page_load(object sender, eventargs e) {     var cn = p in db.attendances              (p.branchid == convert.toint32(dropdownlist1.selectedvalue))                   && (p.semesterid == convert.toint32(dropdownlist2.selectedvalue))              select new              {                  p.attendanceid,                  p.status,                  p.studid,                  p.student.studfirstname,                  p.student.studlastname,                  p.branchid,                  p.semesterid,                  p.branch.branchname,                  p.semester.semestername               };     gridview1.datasource = cn;     gridview1.databind(); } } 

and in design :

            <asp:label id="label1" runat="server" text='<%#eval("studid") %>'></asp:label>             <asp:label id="label2" runat="server" text='<%#eval("studfirstname") %>'></asp:label>             <asp:label id="label3" runat="server" text='<%#eval("studlastname") %>'></asp:label>            <asp:checkbox id="checkbox1" text='<%#eval("status") %>' runat="server" />          </itemtemplate>     </asp:templatefield> </columns> </asp:gridview> 

assing data

 text='<%# eval("studid").tostring() %>'   text='<%# eval("status").tostring() %>' 

or specify gridview columns integer type.