C#开发一应用的总结
要搭建测试环境。
Webbrowser使用方面:
重新加载一页面后,要获取新的内容要使用重新使用browser.Document获取;
HtmlElement的GetElementsByTagName(html标记)是HtmlElement中包括的所有标记的集合,如果相同元素有嵌套时要注意。如:
<table>
<tr>
<td>1</td>
</tr>
<tr>
<td>
<table>
<tr>
<td>2</td>
</tr><tr>
<td>3</td>
</tr>
</table>
</td>
</tr>
</table>
如果获取最外层table节点为HtmlElement he,此时使用he.GetElementsByTagName(“tr”),则包含4个元素:
0:
<tr>
<td>1</td>
</tr>
1:
<tr>
<td>
<table>
<tr>
<td>2</td>
</tr><tr>
<td>3</td>
</tr>
</table>
</td>
</tr>
2:
<tr>
<td>2</td>
</tr>
3:
<tr>
<td>3</td>
</tr>
如果要获取class属性,要使用HtmlElement he;he.getAttribute(“className”); 或he.getAttribute(“classname”); 即不区分大小写
下拉列表设置属性:
he.SetAttribute("value", "2013-1-1");
he.RaiseEvent("onChange"); //触发onChange事件,如果在后续代码中使用he.invokeScript(js名称);这个可以不用写
其它:
Dictionary使用中如果使用foreach travel时不能进行更改(增加、删除、修改),否则会报错:
Collection was modified; enumeration operation may not execute.
遍历并修改:
#region Dictionary Travel modify
public static void mainTest()
{
Dictionary<String, Int32> dic = new Dictionary<String, Int32>();
dic.Add("1", 1);
dic.Add("2", 2);
dic.Add("3", 3);
foreachTravelDic(dic);
modifyDic1(dic);
foreachTravelDic(dic);
modifyDic2(dic);
foreachTravelDic(dic);
Console.ReadKey();
}
public static void foreachTravelDic(Dictionary<String, Int32> dic)
{
foreach (KeyValuePair<String, Int32> kvp in dic)
{
Console.WriteLine(String.Format("Key:{0}; Value:{1}", kvp.Key, kvp.Value));
//dic[kvp.Key] = 2;//此操作会报错
}
}
private static void modifyDic2(Dictionary<String, Int32> dic)
{
String[] keyStr = dic.Keys.ToArray<String>();
for (int i = 0; i < keyStr.Length; i++)
{
dic[keyStr[i]] = dic[keyStr[i]] + 22;
}
}
private static void modifyDic1(Dictionary<String, Int32> dic)
{
int dicCount = dic.Keys.Count;
String[] strKey = new String[dicCount];
dic.Keys.CopyTo(strKey, 0);//支持.net2.0
for (int i = 0; i < strKey.Length; i++)
{
if (dic.ContainsKey(strKey[i]))
{
dic[strKey[i]] = dic[strKey[i]] + 11;
}
}
}
#endregion
output:
补充:
foreach在travel Dictionary时报错的原因:
http://www.cnblogs.com/dudu/archive/2006/07/31/464391.html
在执行foreach时,其他线程对_dictionary进行了Add操作,改变了_dictionary中的数据,从而产生了上述的异常信息。
那为什么会产生这样的异常信息呢?
foreach实际上执行的代码是:
Dictionary<int, int>.Enumerator enumerator = _dictionary.GetEnumerator();
try
{
while (enumerator.MoveNext())
{
}
}
finally
{
IDisposable d = enumerator as IDisposable;
if (d != null) d.Dispose();
}
通过Reflector查看Dictionary<TKey, TValue>.Enumerator.MoveNext()源代码,我们会发现开始处有这样的代码:
if (this.version != this.dictionary.version)
{
ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumFailedVersion);
}
而异常就是在这里发生的,因为Add操作时改变了Dictionary的version,通过查看Insert(TKey key, TValue value, bool add)的源代码会看出。
我觉得Dictionary<TKey, TValue>应该提供一个方法,可以设置在MoveNext时是否进行版本检查,因为有时在foreach操作时,可能并不关心Dictionary中的数据是否被修改,我遇到的就是这样的情况,现在由于这个问题而不能使用foreach,而只能采取其他方法遍历Dictionary<TKey, TValue>中的数据。
Dictionary类型在作为参数传递时:
public static void Main(String[] args) {
#region test Dic
IDictionary<String,String> sumDic=new Dictionary<String,String>();
IDictionary<String, String> secDic = new Dictionary<String, String>();
sumDic.Add("ak","av");
sumDic.Add("bk", "bv");
sumDic.Add("ck", "cv");
sumDic.Add("dk", "dv");
sumDic.Add("ek", "ev");
secDic = testDic(sumDic);//引用传递
foreach (KeyValuePair<String, String> kvp in sumDic)
{
Console.WriteLine(String.Format("{0}====>{1}",kvp.Key,kvp.Value));
}
Console.WriteLine("----------------------------");
foreach (KeyValuePair<String, String> kvp in secDic)
{
Console.WriteLine(String.Format("{0}====>{1}", kvp.Key, kvp.Value));
}
// output:
// ak====>av
// bk====>bv
// ck====>cv
// ek====>ev
//----------------------------
// dk====>dv
#endregion
Console.ReadKey();
}
private static IDictionary<String, String> testDic(IDictionary<String, String> sumDic)
{
IDictionary<String, String> secDic = new Dictionary<String, String>();
String[] keysStr=sumDic.Keys.ToArray<String>();
for (int i = 0; i < keysStr.Length; i++)
{
if (sumDic[keysStr[i]].Equals("dv"))
{
secDic.Add(keysStr[i], sumDic[keysStr[i]]);
sumDic.Remove(keysStr[i]);
}
}
return secDic;
}
出现的问题:
1、因业务需要更改了几个关键方法,程序没有报异常,但是有一个方法一直没有执行,一直很困惑
由于开发环境和生产环境分离,也无法在现网调试,只能分析代码,最后发现问题就在改的方法上,中间的过渡方法执行了另一个操作,但是没有将值返回,导致向上层传递了空Dictionary,虽然没有报错,但不满足另一个方法的执行条件。。。。
2、日志输出时忽略了一些关键信息,需先规划好要输入哪些必要信息;
3、IDictionary<String, int[]> 数组作为dic的value时出现的问题:
数组是引用类型,如果在第二次使用时没有实始化就重新使用,会影响到以前的值:
有问题的:
public static void TestDicArray() { Dictionary<String, int[]> dic = new Dictionary<String, int[]>(); int[] valueArray=new int[2]; valueArray[0] = 1; valueArray[1] = 1; dic.Add("test1",valueArray); //valueArray = new int[2]; valueArray[0] = 2; valueArray[1] = 2; dic.Add("test2", valueArray); //valueArray = new int[2]; valueArray[0] = 3; valueArray[1] = 3; dic.Add("test3", valueArray); // valueArray = new int[2]; valueArray[0] = 4; valueArray[1] = 4; dic.Add("test4", valueArray); // valueArray = new int[2]; valueArray[0] = 5; valueArray[1] = 5; dic.Add("test5", valueArray); foreach (KeyValuePair<String,int[]> kvp in dic) { Console.WriteLine(kvp.Key); int[] tempInt = kvp.Value; Console.WriteLine(tempInt[0]+"\t"+tempInt[1]); Console.WriteLine(dic[kvp.Key][0]+"\t"+dic[kvp.Key][1]); } }
public static void TestDicArray() {
Dictionary<String, int[]> dic = new Dictionary<String, int[]>();
int[] valueArray=new int[2];
valueArray[0] = 1;
valueArray[1] = 1;
dic.Add("test1",valueArray);
valueArray = new int[2];
valueArray[0] = 2;
valueArray[1] = 2;
dic.Add("test2", valueArray);
valueArray = new int[2];
valueArray[0] = 3;
valueArray[1] = 3;
dic.Add("test3", valueArray);
valueArray = new int[2];
valueArray[0] = 4;
valueArray[1] = 4;
dic.Add("test4", valueArray);
valueArray = new int[2];
valueArray[0] = 5;
valueArray[1] = 5;
dic.Add("test5", valueArray);
foreach (KeyValuePair<String,int[]> kvp in dic)
{
Console.WriteLine(kvp.Key);
int[] tempInt = kvp.Value;
Console.WriteLine(tempInt[0]+"\t"+tempInt[1]);
Console.WriteLine(dic[kvp.Key][0]+"\t"+dic[kvp.Key][1]);
}
}
OutPut:
//input value attribute;InnerText is null HtmlElementCollection hecSelects = hd.GetElementsByTagName("input"); foreach (HtmlElement heSelect in hecSelects) { showMsgInText("value:"+heSelect.GetAttribute("value")); showMsgInText("InnerText:" + heSelect.InnerText); }