aim*_*rer 30 linq asp.net parameters json jqgrid
这个工作!..但还需要一件事......
好的,所以这既是"评论"也是问题.首先,是可以帮助其他人搜索asp.net webmethod/jqGrid方法的工作示例.下面的代码完全适用于从jqGrid发送/接收JSON参数,以便使用LINQ进行正确的分页,排序,过滤(仅使用单个搜索)..它使用来自这里和那里的部分......
第二,是我的问题: 有没有人确定一种适当的方法来计算被发送到代码隐藏的动态运算符？由于客户端可能发送"eq"(等于),"cn"(包含)"gt"(大于),我需要一种更好的方法来动态生成whereclause,这不仅限于我构建whereclause字符串"="或"<>",但可以包含动态Linq的使用能力.Contains或.EndsWith等.
我可能需要某种谓词构建器功能..
截至目前处理此问题的代码(有效但有限):
if (isSearch) {
searchOper = getOperator(searchOper); // need to associate correct operator to value sent from jqGrid
string whereClause = String.Format("{0} {1} {2}", searchField, searchOper, "@" + searchField);
//--- associate value to field parameter
Dictionary<string, object> param = new Dictionary<string, object>();
param.Add("@" + searchField, searchString);
query = query.Where(whereClause, new object[1] { param });
}
随着节目.........
==================================================
<script type="text/javascript">
$(document).ready(function() {
var grid = $("#grid");
$("#grid").jqGrid({
// setup custom parameter names to pass to server
prmNames: {
search: "isSearch",
nd: null,
rows: "numRows",
page: "page",
sort: "sortField",
order: "sortOrder"
},
// add by default to avoid webmethod parameter conflicts
postData: { searchString: '', searchField: '', searchOper: '' },
// setup ajax call to webmethod
datatype: function(postdata) {
$(".loading").show(); // make sure we can see loader text
$.ajax({
url: 'PageName.aspx/getGridData',
type: "POST",
contentType: "application/json; charset=utf-8",
data: JSON.stringify(postdata),
dataType: "json",
success: function(data, st) {
if (st == "success") {
var grid = $("#grid")[0];
grid.addJSONData(JSON.parse(data.d));
}
},
error: function() {
alert("Error with AJAX callback");
}
});
},
// this is what jqGrid is looking for in json callback
jsonReader: {
root: "rows",
page: "page",
total: "totalpages",
records: "totalrecords",
cell: "cell",
id: "id", //index of the column with the PK in it
userdata: "userdata",
repeatitems: true
},
colNames: ['Id', 'First Name', 'Last Name'],
colModel: [
{ name: 'id', index: 'id', width: 55, search: false },
{ name: 'fname', index: 'fname', width: 200, searchoptions: { sopt: ['eq', 'ne', 'cn']} },
{ name: 'lname', index: 'lname', width: 200, searchoptions: { sopt: ['eq', 'ne', 'cn']} }
],
rowNum: 10,
rowList: [10, 20, 30],
pager: jQuery("#pager"),
sortname: "fname",
sortorder: "asc",
viewrecords: true,
caption: "Grid Title Here",
gridComplete: function() {
$(".loading").hide();
}
}).jqGrid('navGrid', '#pager', { edit: false, add: false, del: false },
{}, // default settings for edit
{}, // add
{}, // delete
{ closeOnEscape: true, closeAfterSearch: true}, //search
{}
)
});
</script>
==================================================
[WebMethod]
public static string getGridData(int? numRows, int? page, string sortField, string sortOrder, bool isSearch, string searchField, string searchString, string searchOper) {
string result = null;
MyDataContext db = null;
try {
//--- retrieve the data
db = new MyDataContext("my connection string path");
var query = from u in db.TBL_USERs
select new User {
id = u.REF_ID,
lname = u.LAST_NAME,
fname = u.FIRST_NAME
};
//--- determine if this is a search filter
if (isSearch) {
searchOper = getOperator(searchOper); // need to associate correct operator to value sent from jqGrid
string whereClause = String.Format("{0} {1} {2}", searchField, searchOper, "@" + searchField);
//--- associate value to field parameter
Dictionary<string, object> param = new Dictionary<string, object>();
param.Add("@" + searchField, searchString);
query = query.Where(whereClause, new object[1] { param });
}
//--- setup calculations
int pageIndex = page ?? 1; //--- current page
int pageSize = numRows ?? 10; //--- number of rows to show per page
int totalRecords = query.Count(); //--- number of total items from query
int totalPages = (int)Math.Ceiling((decimal)totalRecords / (decimal)pageSize); //--- number of pages
//--- filter dataset for paging and sorting
IQueryable<User> orderedRecords = query.OrderBy(sortfield);
IEnumerable<User> sortedRecords = orderedRecords.ToList();
if (sortorder == "desc") sortedRecords= sortedRecords.Reverse();
sortedRecords = sortedRecords
.Skip((pageIndex - 1) * pageSize) //--- page the data
.Take(pageSize);
//--- format json
var jsonData = new {
totalpages = totalPages, //--- number of pages
page = pageIndex, //--- current page
totalrecords = totalRecords, //--- total items
rows = (
from row in sortedRecords
select new {
i = row.id,
cell = new string[] {
row.id.ToString(), row.fname, row.lname
}
}
).ToArray()
};
result = Newtonsoft.Json.JsonConvert.SerializeObject(jsonData);
} catch (Exception ex) {
Debug.WriteLine(ex);
} finally {
if (db != null) db.Dispose();
}
return result;
}
/* === User Object =========================== */
public class User {
public int id { get; set; }
public string lname { get; set; }
public string fname { get; set; }
}
==================================================
为了在LINQ中拥有动态的OrderBy子句,我不得不将一个类引入我的AppCode文件夹,名为"Dynamic.cs".您可以在此处从下载中检索文件.您将在"DynamicQuery"文件夹中找到该文件.该文件将使您能够使用动态ORDERBY子句,因为除了初始加载之外我们不知道我们要过滤哪个列.
为了将JSON从C-sharp序列化回JS,我在这里找到了James Newton-King JSON.net DLL:http://json.codeplex.com/releases/view/37810 .下载后,有一个"Newtonsoft.Json.Compact.dll",您可以在Bin文件夹中添加它作为参考
这是我使用System的USING块; 使用System.Collections; 使用System.Collections.Generic; 使用System.Linq; 使用System.Web.UI.WebControls; 使用System.Web.Services; 使用System.Linq.Dynamic;
对于JavaScript的引用,我使用的情况下,各自的顺序,可以帮助一些人以下脚本:1)jQuery的1.3.2.min.js ... 2)jQuery的UI的1.7.2.custom.min. js ... 3)json.min.js ... 4)i18n/grid.locale-en.js ... 5)jquery.jqGrid.min.js
对于CSS,我使用jqGrid的必需品以及jQuery UI主题:1)jquery_theme/jquery-ui-1.7.2.custom.css ... 2)ui.jqgrid.css
将参数从JS获取到WebMethod而不必解析后端的反序列化字符串或必须设置一些JS逻辑来切换不同数量参数的方法的关键是这个块
postData: { searchString: '', searchField: '', searchOper: '' },
当您实际执行搜索时,仍会正确设置这些参数,然后在"重置"或希望网格不进行任何过滤时重置为空
希望这有助于其他人!!!! 感谢您有时间阅读和回复有关在运行时与操作员一起构建whereclause的动态方法
考虑这个扩展方法，它将字符串转换为 MemberExpression：
public static class StringExtensions
{
public static MemberExpression ToMemberExpression(this string source, ParameterExpression p)
{
if (p == null)
throw new ArgumentNullException("p");
string[] properties = source.Split('.');
Expression expression = p;
Type type = p.Type;
foreach (var prop in properties)
{
var property = type.GetProperty(prop);
if (property == null)
throw new ArgumentException("Invalid expression", "source");
expression = Expression.MakeMemberAccess(expression, property);
type = property.PropertyType;
}
return (MemberExpression)expression;
}
}
下面的方法将您拥有的字符串转换为 Lambda 表达式，您可以使用它来过滤 Linq 查询。它是一个通用方法，以 T 为域实体。
public virtual Expression<Func<T, bool>> CreateExpression<T>(string searchField, string searchString, string searchOper)
{
Expression exp = null;
var p = Expression.Parameter(typeof(T), "p");
try
{
Expression propertyAccess = searchField.ToExpression(p);
switch (searchOper)
{
case "bw":
exp = Expression.Call(propertyAccess, typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) }), Expression.Constant(searchString));
break;
case "cn":
exp = Expression.Call(propertyAccess, typeof(string).GetMethod("Contains", new Type[] { typeof(string) }), Expression.Constant(searchString));
break;
case "ew":
exp = Expression.Call(propertyAccess, typeof(string).GetMethod("EndsWith", new Type[] { typeof(string) }), Expression.Constant(searchString));
break;
case "gt":
exp = Expression.GreaterThan(propertyAccess, Expression.Constant(searchString, propertyAccess.Type));
break;
case "ge":
exp = Expression.GreaterThanOrEqual(propertyAccess, Expression.Constant(searchString, propertyAccess.Type));
break;
case "lt":
exp = Expression.LessThan(propertyAccess, Expression.Constant(searchString, propertyAccess.Type));
break;
case "le":
exp = Expression.LessThanOrEqual(propertyAccess, Expression.Constant(searchString, propertyAccess.Type));
break;
case "eq":
exp = Expression.Equal(propertyAccess, Expression.Constant(searchString.ToType(propertyAccess.Type), propertyAccess.Type));
break;
case "ne":
exp = Expression.NotEqual(propertyAccess, Expression.Constant(searchString, propertyAccess.Type));
break;
default:
return null;
}
return (Expression<Func<T, bool>>)Expression.Lambda(exp, p);
}
catch
{
return null;
}
}
所以，你可以这样使用它：
db.TBL_USERs.Where(CreateExpression<TBL_USER>("LAST_NAME", "Costa", "eq"));