（分页、排序等）asp.net 2.0下一个标准GRIDVIEW功能的实现

在asp.net 2.0下，gridview是十分方便的了，加一个DATASOURCE系列的控件的话，就可以马上和gridview绑定，十分方便。但其实也可以
使用datatable或者dataview的，这个时候就不是用datasource系列控件了。下面讲下如何在asp.net 2.0下，实现gridview控件的翻页，各列排序，
编辑的功能。
首先，我们读取的是northwind数据库中的employee表。放置一个gridview后，添加几个绑定的列，代码如下
<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True"
AutoGenerateColumns="False" CellPadding="4" ForeColor="#333333" GridLines="None"
Width="100%" DataKeyNames="EmployeeID" OnPageIndexChanging="GridView1_PageIndexChanging" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating" OnSorting="GridView1_Sorting" PageSize="3" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowCommand="GridView1_RowCommand">
<FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<Columns>
<asp:BoundField DataField="employeeid" HeaderText="Employee ID" ReadOnly="True" />
<asp:BoundField DataField="firstname" HeaderText="First Name" SortExpression="firstname" />
<asp:BoundField DataField="lastname" HeaderText="Last Name" SortExpression="lastname" />
<asp:CommandField ShowEditButton="True" />
</Columns>
<RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
<SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
<PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
<HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>

首先，我们要实现分页，把AllowPaging设置为true,并设置每页的分页条数，最后在codebehind中写入
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
BindGrid();
}
为了实现每列都可以自动点击排序，可以设置allowsorting=true,然后设置OnSorting="GridView1_Sorting"，其中gridview_sorting
代码为
protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
{
ViewState["sortexpression"] = e.SortExpression;

if (ViewState["sortdirection"] == null)
{
ViewState["sortdirection"] = "asc";
}
else
{
if (ViewState["sortdirection"].ToString() == "asc")
{
ViewState["sortdirection"] = "desc";
}
else
{
ViewState["sortdirection"] = "asc";
}
}
BindGrid();
}
很明显，设置viewsate来保存每次排序时的顺序，上面的相信很容易理解。
最后，实现编辑功能，因为在aspx页面中已经设置了OnRowEditing="GridView1_RowEditing"，其中GridView1_RowEditing的代码为
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
int empid;
string fname, lname;
empid = int.Parse(GridView1.Rows[e.RowIndex].Cells[0].Text);
fname = ((TextBox)GridView1.Rows[e.RowIndex].Cells[1].Controls[0]).Text;
lname = ((TextBox)GridView1.Rows[e.RowIndex].Cells[2].Controls[0]).Text;

SqlConnection cnn = new SqlConnection(@"data source=localhost;initial catalog=northwind;user id=sa;password=123456");
cnn.Open();
SqlCommand cmd = new SqlCommand("update employees set firstname=@fname,lastname=@lname where employeeid=@empid", cnn);
cmd.Parameters.Add(new SqlParameter("@fname",fname));
cmd.Parameters.Add(new SqlParameter("@lname", lname));
cmd.Parameters.Add(new SqlParameter("@empid", empid));
cmd.ExecuteNonQuery();
cnn.Close();

GridView1.EditIndex = -1;
BindGrid();
}
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
GridView1.EditIndex = e.NewEditIndex;
BindGrid();
}
protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
GridView1.EditIndex = -1;
BindGrid();
}

可以看到，上面的代码和asp.net 1.1版本的其实原理是差不多的。最后，bindgrid()的过程很简单，为绑定咯
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter("select * from employees", @"data source=localhost;initial catalog=northwind;user id=sa;password=123456");
da.Fill(ds,"employees");
DataView dv = ds.Tables[0].DefaultView;

if (ViewState["sortexpression"] != null)
{
dv.Sort = ViewState["sortexpression"].ToString() + " " + ViewState["sortdirection"].ToString();
}

GridView1.DataSource=dv;
GridView1.DataBind();

这里gridview绑定的是dataview,并且用dv.sort设定了每次排序的顺序，也就是说，每次排序后其顺序都是保持不变的。
当然最后是page_load事件咯
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
BindGrid();
}
}