Ajax linkage between provinces, cities, and counties

HTML code

 

1. <Form ID = "form1" runat = "server">
2. <Div>
3. <Div id = "DV">
4. <Table>
5. <Tr>
6. <TD> <asp: dropdownlist id = "ddlprovince" runat = "server" onchange = "provincechange ()"> </ASP: dropdownlist> </TD>
7. <TD> <select id = "ddlcity" runat = "server" onchange = "citychange ()"> </SELECT> </TD>
8. <TD> <select id = "ddlarea" runat = "server"> </SELECT> </TD>
9. </Tr>
10. </Table>
11. <Br/>
12. <Asp: button id = "button1" runat = "server" onclick = "button?click1" text = ""/> </div>
13. <SCRIPT>
15. Function provincechange ()
16. {
17. VaR OBJ = Document. getelementbyid ("ddlprovince"). Options [document. getelementbyid ("ddlprovince"). selectedindex];
18. VaR city = Document. getelementbyid ("ddlcity ");
19. VaR area = Document. getelementbyid ("ddlarea ");
20. VaR strcitys = _ default. getparent (obj. Value). value;
21. If (strcitys. indexof (",")> 0)
22. {
23. City. Length = 0;
24. City. Options [0] = New Option ("select", "-1 ");
25. Area. Length = 0;
26. Area. Options [0] = New Option ("select", "-1 ");
27. VaR citys = strcitys. Split ("-");
28. For (VAR I = 0; I <Citys. length; I ++)
29. {
30. City. options [I + 1] = New Option (citys [I]. split (",") [0], citys [I]. split (",") [1]);
31. }
32. }
33. Else
34. {
35. City. Length = 0;
36. City. Options [0] = New Option ("select", "-1 ");
37. }
38. }
40. Function citychange ()
41. {
42. VaR OBJ = Document. getelementbyid ("ddlcity"). Options [document. getelementbyid ("ddlcity"). selectedindex];
43. VaR city = Document. getelementbyid ("ddlarea ");
44. VaR strcitys = _ default. getparent (obj. Value). value;
45. If (strcitys. indexof (",")> 0)
46. {
47. City. Length = 0;
48. City. Options [0] = New Option ("select", "-1 ");
49. VaR citys = strcitys. Split ("-");
50. For (VAR I = 0; I <Citys. length; I ++)
51. {
52. City. options [I + 1] = New Option (citys [I]. split (",") [0], citys [I]. split (",") [1]);
53. }
54. }
55. Else
56. {
57. City. Length = 0;
58. City. Options [0] = New Option ("select", "-1 ");
59. }
60. }
61. </SCRIPT>
62. </Div>
63. </Form>

 

 

CS code

 

 

1. Public sqldmo = new sqldmo ();
3. Protected void page_load (Object sender, eventargs E)
4. {
6. If (! Ispostback)
7. {
8. Setprovince ();
9. Listitem listcity = new listitem ("select", "-1 ");
10. Ddlcity. Items. insert (0, listcity );
11. Listitem listarea = new listitem ("select", "-1 ");
12. Ddlarea. Items. insert (0, listarea );
14. }
15. Ajaxpro. Utility. registertypeforajax (typeof (_ default ));
16. }
18. Private void setprovince ()
19. {
20. Datatable dtprovince = sqldmo. Query ("select ass_id as ID, ass_dis as name from assort where ass_name = 'province '");
21. Ddlprovince. datasource = dtprovince;
22. Ddlprovince. datatextfield = "name ";
23. Ddlprovince. datavaluefield = "ID ";
24. Ddlprovince. databind ();
25. Listitem listprovince = new listitem ("select", "-1 ");
26. Ddlprovince. Items. insert (0, listprovince );
27. }
29. [Ajaxpro. ajaxmethod]
30. Public String getparent (string parentid)
31. {
32. Datatable dtcity = sqldmo. Query ("select ass_id as ID, ass_dis as name from assort where ass_fid = '" + parentid + "'");
33. String strcity = "";
34. For (INT I = 0; I <dtcity. Rows. Count; I ++)
35. {
36. Strcity + = dtcity. rows [I] ["name"]. tostring (). trim () + "," + dtcity. rows [I] ["ID"]. tostring (). trim () + "-";
37. If (I = dtcity. Rows. Count-1) strcity = strcity. substring (0, strcity. Length-1 );
38. }
40. Return strcity;
41. }