js模板方法的思路及实现
在js中如何实现设计模式中的模板方法？
思路的产生必然要求熟悉js，如何实现？就很简单了，都知道在js中如果定义两个相同名称的方法，前一个方法就会被后一个方法覆盖掉，使用此特点就可以实现模板方法。
例如在实际的项目中有很多页面操作的步骤基本相同，但局部细节却不一样。例如在我所在的项目中，就有很多展示数据库记录的页面，每个页面都存在读取记录，查询记录，增加删除，修改记录等相同的操作，但对应的后台方法却不一样。
function ListCommon2() {
var urlAdd;
var urlAjax;
var tableid;
var titleText="";
var winid = "#win";
var columns;
var toolbars;
var queryParams;
var colkey;
var toolbarsType
this.initList = function (aurlAdd, aurlAjax, atableid, atitleText, awinid, acolumns, atoolbarsType) {
urlAdd = aurlAdd;
urlAjax = aurlAjax;
if (atableid) {
tableid = atableid;
}
if (atitleText) {
titleText = atitleText;
}
if (atitleText) {
winid = awinid;
}
columns = acolumns;
toolbarsType = atoolbarsType;
};
this.initData = function () {
if (!toolbarsType) {
toolbars = [{ text: '添加', iconCls: 'icon-add', handler: Add }, '-', { text: '编辑', iconCls: 'icon-edit', handler: this.Edit }
, '-', { text: '删除', iconCls: 'icon-cancel', handler: this.delMsg }
];
} else {
toolbars = toolbarsType;
}
queryParams = this.GetqueryParams();
$(tableid).datagrid({
url: urlAjax + '?OperationType=list',
columns: columns,
toolbar: toolbars,
idField: colkey,
pagination: true,
pageSize: 20,
sortName: colkey,
sortOrder: 'desc',
rownumbers: true, fitColumns: true,
striped: true,
method: "post",
striped: true,
queryParams: this.GetqueryParams(),
showFooter: true
, pageList: [10, 20, 30, 40, 50]
});
$("#add").click(function (e) {
Add();
})
$("#edit").bind('click', { obj: this }, function (event) {
event.data.obj. Edit();
})
$("#del").bind('click', { obj: this }, function (event) {
event.data.obj.delMsg();
})
$("#btnQuery").bind('click', { obj: this }, function (event) {
var queryParamsnew = event.data.obj.GetqueryParams();
$(tableid).datagrid('load', queryParamsnew)
})
}
this.GetqueryParams = function () {
var NameList = this.Getcolsinfo();
var otherQueryParams = this.GetOtherQueryParams();
if (!otherQueryParams) {
return { colkey: colkey, colsinfo: NameList }
}
else {
return otherQueryParams;
}
}
this.GetOtherQueryParams = function () {
return null;
}
this.Getcolsinfo = function () {
var fieldNameList = [];
if (columns.length > 0) {
for (var i = 0; i < columns[0].length; i++) {
fieldNameList.push(columns[0][i].field);
}
}
else {
alert("未绑定数据");
}
colkey = fieldNameList[fieldNameList.length-1];
var NameList = fieldNameList.join(",");
return NameList
}
function Add() {
var _content = '<iframe id="FRMdetail" frameborder="0" src=' + urlAdd + ' style="width:100%;height:100%;" ></iframe>';
$(winid).dialog({
width: 600,
height: 400,
modal: true,
content: _content,
title: "增加" + titleText,
draggable: true,
resizable: true,
shadow: true,
minimizable: false
});
}
this.Edit = function (editId) {
var id; var obj = typeof (editId);
if (!editId || obj == "object") {
var items = $(tableid).datagrid('getSelections');
var length = items.length;
if (length == 0) {
$.messager.alert('提示', '请选择一条记录然后编辑');
return;
} else if (length > 1) {
$.messager.alert('提示', '由于一次只能编辑一条记录，所以只能修改第一条记录');
return;
}
id = GetId(items[0]);
}
else {
id = editId;
}
var _content = '<iframe id="FRMdetail" frameborder="0" src=' + urlAdd + '?Id=' + id + ' style="width:100%;height:100%;" ></iframe>';
$(winid).dialog({
width: 600,
height: 400,
modal: true,
content: _content,
title: "修改" + titleText,
draggable: true,
resizable: true,
shadow: true,
minimizable: false
});
}
this.windowclose = function () {
$(winid).window('close');
}
this.SaveOkCallback = function () {
this.windowclose();
$(tableid).datagrid('reload');
$(tableid).datagrid('unselectAll');
}
this.delMsg = function (delId) {
var length = 1;
var id;
var items; var obj = typeof (delId);
if (!delId || obj == "object") {
items = $(tableid).datagrid('getSelections');
length = items.length;
if (length == 0) {
$.messager.alert('提示', '请至少选择一条记录然后删除');
return;
}
}
else {
id = delId;
}
var text = '你确认删除' + length + '条记录吗?';
if (length == 1) {
text = '你确认删除该条记录吗?';
}
$.messager.confirm('提示', text, function (r) {
if (r) {
if (!delId) {
var idList = [];
$.each(items,
function (key, value) {
var id = GetId(value); // in case we're changing the key
idList.push(id);
});
id = idList.join(",");
}
del(id)
}
});
}
function del(id) {
$.ajax({ type: "post",
url: urlAjax + "?OperationType=del&id=" + id,
success: function (msg) {
var obj = jQuery.parseJSON(msg);
if (obj.IsSuccess == true) {
$.messager.alert('提示', obj.Msg);
selectcallback();
}
else {
$.messager.alert('提示', obj.Msg);
}
}
});
}
function selectcallback() {
SaveOkCallback();
}
}
function ListCommon2() {
var urlAdd;
var urlAjax;
var tableid;
var titleText="&quo补充：web前端 , JavaScript ,
