C# 数据集和数据表的问题
我正在研究一种从学生数据库中提取学生成绩的方法,其中所有年份和班级的所有科目成绩都存储在一个表中,因此此函数将提取特定部门班级的成绩,并将其存储在数据集中的数据表中,这就是我到目前为止编写的代码C# 数据集和数据表的问题,c#,asp.net,C#,Asp.net,我正在研究一种从学生数据库中提取学生成绩的方法,其中所有年份和班级的所有科目成绩都存储在一个表中,因此此函数将提取特定部门班级的成绩,并将其存储在数据集中的数据表中,这就是我到目前为止编写的代码 public void Button1_Click(object sender, EventArgs e) { con.Open(); cmd.CommandText = "SELECT Course.Course_code, Course.Course_name, co
public void Button1_Click(object sender, EventArgs e)
{
con.Open();
cmd.CommandText = "SELECT Course.Course_code, Course.Course_name, courseyear.level FROM Course INNER JOIN courseyear ON Course.Course_code = courseyear.Course_code WHERE (courseyear.dep = '" + dep.SelectedValue + "') AND (courseyear.subdep = '" + subdep.SelectedValue + "') AND (courseyear.year = '" + year.SelectedValue + "') AND (courseyear.level = '" + level2.SelectedValue + "')";
da = new SqlDataAdapter(cmd.CommandText, con);
ds.Clear();
da.Fill(ds, "junk");
cmd.CommandText = "SELECT Course.Course_code, Course.Course_name, courseyear.level FROM Course INNER JOIN courseyear ON Course.Course_code = courseyear.Course_code WHERE (courseyear.dep = '" + dep.SelectedValue + "') AND (courseyear.subdep = '" + subdep.SelectedValue + "') AND (courseyear.year = '" + year.SelectedValue + "') AND (courseyear.level = '" + level2.SelectedValue + "')";
da = new SqlDataAdapter(cmd.CommandText, con);
da.Fill(ds, "subs");
ds.Tables.Add("res");
cnum = ds.Tables["junk"].Rows.Count;
//l7de hna kweseen
ds.Tables["res"].Columns.Add(new DataColumn("index",typeof(string)));
ds.Tables["res"].Columns.Add(new DataColumn("name", typeof(string)));
//int rnum = ds.Tables["res"].Rows.Count;
for (int x = 0; x < cnum-1; x++) {
ds.Tables["res"].Columns.Add(new DataColumn(ds.Tables["junk"].Rows[x].ItemArray[0].ToString(), typeof(string)));
}//done inserting subjects
dr = ds.Tables["res"].NewRow();
ds.Tables["junk"].Clear();
cmd.CommandText = "SELECT id, name FROM Students WHERE (dep ='"+dep.SelectedValue+"') AND (class = '"+level2.SelectedValue+"') AND (subDep ='"+subdep.SelectedValue+"')";
da = new SqlDataAdapter(cmd.CommandText, con);
da.Fill(ds, "junk");
int snum = ds.Tables["junk"].Rows.Count;
for (int x = 0; x < snum; x++)
{
dr = ds.Tables["res"].NewRow();
dr.ItemArray[0] = ds.Tables["junk"].Rows[x].ItemArray[0];
dr.ItemArray[1] = ds.Tables["junk"].Rows[x].ItemArray[1];
//ds.Tables["res"].Rows.Add(dr);
}//done inserting students
ShowPopUpMsg(ds.Tables["res"].Rows.Count.ToString());//for testing
ShowPopUpMsg(snum.ToString());// for testing
for (int x = 0; x < cnum ;x++ )//for subjects
{
for (int y =0; y < snum;y++)//for students
{
ds.Tables["junk"].Clear();
cmd.CommandText = "select course_work+final_exam as exp from results where student_id = '" + ds.Tables["res"].Rows[y ].ItemArray[0] + "' and course_code = '"+ds.Tables["subs"].Rows[x]+"' ";
da.Fill(ds, "junk");
ds.Tables["res"].Rows[y].ItemArray[x] = ds.Tables["junk"].Rows[0].ItemArray[0];
}
}
ShowPopUpMsg(ds.Tables["junk"].Rows[0].ItemArray[0].ToString());
}
private void ShowPopUpMsg(string msg)
{
StringBuilder sb = new StringBuilder();
sb.Append("alert('");
sb.Append(msg.Replace("\n", "\\n").Replace("\r", "").Replace("'", "\\'"));
sb.Append("');");
ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "showalert", sb.ToString(), true);
}
}</i>
public void按钮1\u单击(对象发送者,事件参数e)
{
con.Open();
cmd.CommandText=“选择Course.Course\u code,Course.Course\u name,courseyear.level从课程内部连接courseyear ON Course.courseyear.Course\u code,其中(courseyear.dep='“+dep.SelectedValue+”)和(courseyear.year.year='+year.SelectedValue+”)和(courseyear.year.year='“+year.SelectedValue+”)(courseyear.level='“+level2.SelectedValue+”)”;
da=新的SqlDataAdapter(cmd.CommandText,con);
ds.Clear();
da.填充(ds,“垃圾”);
cmd.CommandText=“选择Course.Course\u code,Course.Course\u name,courseyear.level从课程内部连接courseyear ON Course.courseyear.Course\u code,其中(courseyear.dep='“+dep.SelectedValue+”)和(courseyear.year.year='+year.SelectedValue+”)和(courseyear.year.year='“+year.SelectedValue+”)(courseyear.level='“+level2.SelectedValue+”)”;
da=新的SqlDataAdapter(cmd.CommandText,con);
da.填充(ds,“接头”);
ds.表。添加(“res”);
cnum=ds.Tables[“junk”].Rows.Count;
//l7de hna Kwesen
ds.Tables[“res”].Columns.Add(新数据列(“索引”,typeof(字符串));
ds.Tables[“res”].Columns.Add(新数据列(“名称”,typeof(字符串));
//int rnum=ds.Tables[“res”].Rows.Count;
对于(int x=0;x
我的问题是,它一直告诉我students for loop上的0位置没有行您可能需要使用两个不同的数据适配器来填充2个不同的数据集。如果您查看它,您正在重新实例化数据适配器,这将重置以前加载的“垃圾邮件”数据集。因此,当您尝试访问“垃圾邮件”时您什么也看不到。请尝试不实例化或使用不同的适配器。首先,for循环是一个无止境的循环。您不增加
y
变量。请参阅此处的for循环头了解(int y=0;y
谢谢,我修复了这个问题,但我仍然使用了两次垃圾表,因为我不再需要以前的结果了