Webform（分页、组合查询）
2024-10-11 10:40:49
一、分页
1.写查询方法：
public List<Student> Select(int PageCount, int PageNumber)
{//PageCount为每页显示条数，PageNumber为当前第几页
List<Student> list = new List<Student>();
cmd.CommandText = "select top " + PageCount + " *from Student where Code not in (select top "+(PageCount * (PageNumber - ))+" Code from Student)";
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
while (dr.Read())
{
Student s = new Student();
s.Code = dr[].ToString();
s.Name = dr[].ToString();
s.Sex = Convert.ToBoolean(dr[]);
s.Birthday = Convert.ToDateTime(dr[]);
s.SubjectCode = dr[].ToString();
s.Nation = dr[].ToString();
list.Add(s);
}
}
conn.Close();
return list;
}
查询方法
2.C#代码
int PageCount = ; //每页显示条数
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
List<Student> list = new StudentData().Select(PageCount,);
Repeater1.DataSource = list;
Repeater1.DataBind();
Label2.Text = "";//第一页
Label3.Text = MaxPageNumber().ToString();//总页数
}
for (int i = ; i <= MaxPageNumber(); i++)
{
DropDownList2.Items.Add(new ListItem(i.ToString(), i.ToString()));
}
}
Page_Load
public int MaxPageNumber()
{
List<Student> list = new StudentData().select(); double de = list.Count / (PageCount * 1.0); int aa = Convert.ToInt32(Math.Ceiling(de));//取上限
return aa;
}
计算总页数
void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
Repeater1.DataSource = new StudentData().Select(PageCount, Convert.ToInt32(DropDownList2.SelectedValue));
Repeater1.DataBind();
Label2.Text = DropDownList2.SelectedValue;
}
快速跳转
void btn_end_Click(object sender, EventArgs e)
{
List<Student> list = new StudentData().Select(PageCount, MaxPageNumber());
Repeater1.DataSource = list;
Repeater1.DataBind();
Label2.Text = MaxPageNumber().ToString();
}
跳转到最后一页
void btn_first_Click(object sender, EventArgs e)
{
List<Student> list = new StudentData().Select(PageCount, );
Repeater1.DataSource = list;
Repeater1.DataBind();
Label2.Text ="";
}
跳转到第一页
void btn_prev_Click(object sender, EventArgs e)
{
int pagec = Convert.ToInt32(Label2.Text) - ;
if (pagec <=)//判断是不是第一页，是的话什么也不干
{
return;
}
List<Student> list = new StudentData().Select(PageCount, pagec);
Repeater1.DataSource = list;
Repeater1.DataBind();
Label2.Text = pagec.ToString();
}
跳转到上一页
void btn_next_Click(object sender, EventArgs e)
{
int pagec = Convert.ToInt32(Label2.Text) + ;
if (pagec > MaxPageNumber())// 判断是不是最后一页，是的话什么也不干
{
return;
}
Repeater1.DataSource = new StudentData().Select(PageCount,pagec);
Repeater1.DataBind();
Label2.Text = pagec.ToString(); }
跳转到下一页
二、组合查询
1.查询方法
public List<Student> Select(string tsql,Hashtable hh)
{
List<Student> list = new List<Student>();
cmd.CommandText = tsql;
cmd.Parameters.Clear();
foreach( string s in hh.Keys)
{
cmd.Parameters.Add(s,hh[s]);
}
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
while (dr.Read())
{
Student s = new Student();
s.Code = dr[].ToString();
s.Name = dr[].ToString();
s.Sex = Convert.ToBoolean(dr[]);
s.Birthday = Convert.ToDateTime(dr[]);
s.SubjectCode = dr[].ToString();
s.Nation = dr[].ToString();
list.Add(s);
}
}
conn.Close();
return list;
}
查询方法
public List<Subject> Select(string name)
{
List<Subject> list = new List<Subject>();
cmd.CommandText = "select *from Subject where SubjectName like @a ";
cmd.Parameters.Clear();
cmd.Parameters.Add("@a","%"+name+"%");
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
while (dr.Read())
{
Subject s = new Subject();
s.SubjectCode = dr[].ToString();
s.SubjectName = dr[].ToString();
list.Add(s);
}
}
conn.Close(); return list;
}
2.c#代码
void Button2_Click(object sender, EventArgs e)
{
int count = ;//判断tsql是否含有where
Hashtable hs = new Hashtable();//哈希表
string tsql = "select * from Student";
//性别
if(!string.IsNullOrEmpty(tb_sex.Text.Trim()))//输入的性别非空
{
if (tb_sex.Text.Trim() == "男")
{
tsql += " where Sex = @a";
hs.Add("@a", "true");
count++;
}
else if (tb_sex.Text.Trim() == "女")
{
tsql += " where Sex = @a";
hs.Add("@a", "false");
count++;
}
}
//年龄
if (!string.IsNullOrEmpty(tb_age.Text.Trim()))//判断年龄输入框是否为空
{
int a = DateTime.Now.Year;
try {//异常保护，输入框只能是数字
int ag= Convert.ToInt32(tb_age.Text.Trim());
int g = a - ag;
DateTime d = Convert.ToDateTime(g.ToString()+"-1-1");
if (DropDownList3.SelectedValue == ">=")//列表框显示值为<=,小于某个年龄
{
if (count == )
{
tsql += " where Birthday " + DropDownList3.SelectedValue + "@b";
}
else
{
tsql += " and Birthday " + DropDownList3.SelectedValue + "@b";
}
hs.Add("@b", d);
}
else//大于某个年龄
{
DateTime dd = Convert.ToDateTime(g.ToString() + "-12-31");
if (count == )
{
tsql += " where Birthday " + DropDownList3.SelectedValue + "@b";
}
else
{
tsql += " and Birthday " + DropDownList3.SelectedValue + "@b";
}
hs.Add("@b", dd);
}
count++;
}
catch {
}
}
if (!string.IsNullOrEmpty(tb_s.Text.Trim()))//专业非空
{
List<Subject> li = new SubjectData().Select(tb_s.Text.Trim());
if (li.Count <= )
{
}
else
{ string u ="";
int cou = ;
foreach(Subject ub in li)
{
u = ub.SubjectCode;
if (cou == )//第一条数据
{
if (count == )
{
tsql += " where SubjectCode =@c";
}
else
{
tsql += " and SubjectCode =@c";
}
hs.Add("@c", u);
cou++;
}
else
{
tsql += " or SubjectCode =@d";
hs.Add("@d", u);
}
}
}
}
Repeater1.DataSource = new StudentData().Select(tsql, hs);
Repeater1.DataBind();
}
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