ASP.NET C# DataTable与Excel互操作示例 - xnfzy

本邮件内容由第三方提供，如果您不想继续收到该邮件，可 点此退订 。

ASP.NET C# DataTable与Excel互操作示例 - xnfzy  阅读原文»

前几天朋友公司开发需要用到Excel的导入导出，需要通过Web将数据库中的内容与Excel互导！问到我，自己以前做过，网上很多类似的解决方案都是使用类似DataGrid或GridView这样的控件直接导入到Excel，方便，但不是很实用，有时候甚至导出的Excel并不是我们需要的格式！记得曾经听邵志东老师讲过ASP.NET下的自动化操作。但一时又没找到相关的代码。在这里我将自己的示例在这贴出，以方便有自己和以后有这方面需要的朋友查询！

页面运行效果如下

“生成DataTable”的作用就是在内在中创建一个DataTablle 然后使用Repeater显示

protected void btnLoadDt_Click(object sender, EventArgs e)
{
BindData(LoadDataTable());
}
//创建DataTable
private DataTable LoadDataTable()
{
DataTable dt = new DataTable();
DataColumn dc = new DataColumn("userName");
dt.Columns.Add(dc);
dc = new DataColumn("userSex");
dt.Columns.Add(dc);

DataRow dr = dt.NewRow();
dr[0] = "fengyan";
dr[1] = "male";
dt.Rows.Add(dr);

dr = dt.NewRow();
dr[0] = "efly";
dr[1] = "male";
dt.Rows.Add(dr);

dr = dt.NewRow();
dr[0] = "楚旋";
dr[1] = "male";
dt.Rows.Add(dr);

return dt;
}

点击DataTablle导出Excel即可将该DataTable 内容导出到指定的Excel中。相关代码如下：

protected void btnExportExcel_Click(object sender, EventArgs e)
{
//得到需要导入Excel的DataTable
DataTable dt = LoadDataTable();
//将其列名添加进去！ （这一步注意是为了方便以后将该Excel导入内存表中 自动创建列名用。）
DataRow dr = dt.NewRow();
dr[0] = "userName";
dr[1] = "userSex";
dt.Rows.InsertAt(dr, 0);

//实例化一个Excel助手工具类
ExcelHelper ex = new ExcelHelper();
//导入所有！（从第一行第一列开始）
ex.DataTableToExcel(dt, 1, 1);
//导出Excel保存的路径！
ex.OutputFilePath = txtExcelPath.Text;
ex.OutputExcelFile();
}

运行后打开生成的Excel如下：

已经将内容导出到Excel。现在在其中添加一行内容

如果要将该Excel再读取到DataTable中比较简单，可以使用ADO.NET
Excel导入DataTable事件代码如下：

protected void btnExcelToDataTable_Click(object sender, EventArgs e)
{
string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + txtFromExcel.Text + ";Extended Properties=Excel 8.0";
//链接Excel
OleDbConnection cnnxls = new OleDbConnection(strConn);
//读取Excel里面有 表Sheet1
OleDbDataAdapter oda = new OleDbDataAdapter("select * from [Sheet1$]", cnnxls);
DataSet ds = new DataSet();
//将Excel里面有表内容装载到内存表中！
oda.Fill(ds);
DataTable dt = ds.Tables[0];
BindData(dt);
}

运行后页面如下：

可以看到从Excel又读回数据并且自动绑定到Repeater上，我们增加的一行数据也正确显示了！
之所以可以正确绑定出来，是因为我们在导出的时候在Excel最上行添加了一行列名，所以可以对应绑定！
实际中更多的是数据库和Excel的互操作！本文讲到DataTable，从DataTable到数据库的转换也是容易的！
数据从Excel导入到DataTable后，我们可以通过?div style="border-bottom:1px solid #aaa;margin-bottom:25px">POJ 1523 无向图的割点 - coding_yuan  阅读原文»

SPF

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 6653		Accepted: 3037

Description

Consider the two networks shown below. Assuming that data moves around these networks only between directly connected nodes on a peer-to-peer basis, a failure of a single node, 3, in the network on the left would prevent some of the still available nodes from communicating with each other. Nodes 1 and 2 could still communicate with each other as could nodes 4 and 5, but communication between any other pairs of nodes would no longer be possible.

Node 3 is therefore a Single Point of Failure (SPF) for this network. Strictly, an SPF will be defined as any node that, if unavailable, would prevent at least one pair of available nodes from being able to communicate on what was previously a fully connected network. Note that the network on the right has no such node; there is no SPF in the network. At least two machines must fail before there are any pairs of available nodes which cannot communicate.

Input

The input will contain the description of several networks. A network description will consist of pairs of integers, one pair per line, that identify connected nodes. Ordering of the pairs is irrelevant; 1 2 and 2 1 specify the same connection. All node numbers will range from 1 to 1000. A line containing a single zero ends the list of connected nodes. An empty network description flags the end of the input. Blank lines in the input file should be ignored.

Output

For each network in the input, you will output its number in the file, followed by a list of any SPF nodes that exist.

The first network in the file should be identified as "Network #1", the second as "Network #2", etc. For each SPF node, output a line, formatted as shown in the examples below, that identifies the node and the number of fully connected subnets that remain when that node fails. If the network has no SPF nodes, simply output the text "No SPF nodes" instead of a list of SPF nodes.

Sample Input

1 2
5 4
3 1
3 2
3 4
3 5
0

1 2
2 3
3 4
4 5
5 1
0

1 2
2 3
3 4
4 6
6 3
2 5
5 1
0

0

Sample Output

Network #1
SPF node 3 leaves 2 subnets

Network #2
No SPF nodes

Network #3
SPF node 2 leaves 2 subnets
SPF node 3 leaves 2 subnets

Source

Greater New York 2000

题意：找出每个割点，然后求出删除这个割点所得的连通分量个数；

注意：输出格式；

1 #include<iostream>
2 #include<algorithm>
3 #include<cstdio>
4 #include<cstring>
5 #include<cstdlib>
6 #include<vector>
7 #include<map>
8 using namespace std;
9 const int maxn=1007;
10 vector<int> G[maxn];
11 int pre[maxn],ans,root,sum,cnt[maxn];
12 bool isroot[maxn];
13 int tarjan(int u,int fa)
14 {
15 int lowu=pre=sum++;
16 int l=G.size();
17 int child=0;
18 for(int i=0;i<l;i++)
19 {
20 int v=G;
21 if(!pre[v]){
22 child++;
23 int lowv=tarjan(v,u);
24 lowu=min(lowv,lowu);
25 if(u==root&&child>1||u!=root&&pre<=lowv){
26 cnt++;
27 }
28 }
29 else if(v!=fa) lowu=min(lowu,pre[v]);
30 }
31 return lowu;
32 }
33 int main()
34 {
35 int a,b,tt=1;
36 bool first=0;
37 while(1){
38 if(first) printf("\n");
39 else first=1;
40 for(int i=0;i<maxn;i++) G.clear();
41 scanf("%d",&a);
42 if(a==0) break;
43 scanf("%d",&b);
44 G[a].push_back(b);G.push_back(a);
45 while(1){
46 scanf("%d",&a);
47 if(a==阅读更多内容