数据控件DataGrid数据控件

DataGrid数据控件是3个数据控件中功能最强大的一个。使用DataGrid控件可以自动显示表的内容。利用DataReader对象或者DataSet对象和DataGrid控件进行绑定，就可以进行数据输出。
1、利用DataGrid控件实现分页

<asp:DataGrid ID="dg" runat="server" AllowPaging="True" BorderColor="Black"
            CellPadding="2" OnPageIndexChanged="ChangePage" PageSize="5">
            <PagerStyle HorizontalAlign="Right" NextPageText="后页" PrevPageText="前页" />
            <AlternatingItemStyle BackColor="#FFFFCD" />
            <HeaderStyle BackColor="#AAAADD" />
</asp:DataGrid>

protected void Page_Load(object sender, EventArgs e)
    {
        BindGrid();
    }

    private void BindGrid()
    {
        string Provider, DataBase, ConnStr, SQL;
        Provider = "Microsoft.Jet.OLEDB.4.0;";
        DataBase = Server.MapPath("person.mdb");
        ConnStr = "Provider=" + Provider + "Data Source=" + DataBase;
        SQL = "select * from grade";
        OleDbDataAdapter da;
        da = new OleDbDataAdapter(SQL, ConnStr);
        DataSet ds = new DataSet();
        da.Fill(ds, "grade");
        dg.DataSource = ds.Tables["grade"].DefaultView;
        dg.DataBind();
    }

    public void ChangePage(object sender, DataGridPageChangedEventArgs e)
    {
        dg.CurrentPageIndex = e.NewPageIndex;
        BindGrid();
    }

可以把前页和后页改成数字显示。修改为PagerStyle-Mode="NumericPages"可以实现数字显示。
一般用表格显示数据的时候，将某列显示成超级链接的形式，用来进一步显示该记录的详细信息。
利用HyperLinkColumn控件设置显示链接的列，DataNavigateUrlField属性表示链接的字段，DataNavigateUrlFormatString属性表示链接的地址。

<asp:DataGrid ID="dg" runat="server" AllowPaging="True" BorderColor="Black"
            CellPadding="2" OnPageIndexChanged="ChangePage" PageSize="5" AutoGenerateColumns="False">
            <PagerStyle HorizontalAlign="Right" NextPageText="后页" PrevPageText="前页" Mode="NumericPages" />
            <AlternatingItemStyle BackColor="#FFFFCD" />
            <HeaderStyle BackColor="#AAAADD" />
            <Columns>
            <asp:HyperLinkColumn DataTextField="学号" HeaderText="学号"
            DataNavigateUrlField="学号"
            DataNavigateUrlFormatString="test.aspx?id={0}"
            Target="_blank" />            
            <asp:BoundColumn DataField="姓名" HeaderText="姓名" />
            <asp:BoundColumn DataField="数学" HeaderText="数学成绩" ItemStyle-HorizontalAlign="Right"/>
            </Columns>
        </asp:DataGrid>

protected void Page_Load(object sender, EventArgs e)
    {
        BindGrid();
    }

    private void BindGrid()
    {
        string Provider, DataBase, ConnStr, SQL;
        Provider = "Microsoft.Jet.OLEDB.4.0;";
        DataBase = Server.MapPath("person.mdb");
        ConnStr = "Provider=" + Provider + "Data Source=" + DataBase;
        SQL = "select * from grade";
        OleDbDataAdapter da;
        da = new OleDbDataAdapter(SQL, ConnStr);
        DataSet ds = new DataSet();
        da.Fill(ds, "grade");
        dg.DataSource = ds.Tables["grade"].DefaultView;
        dg.DataBind();
    }

    public void ChangePage(object sender, DataGridPageChangedEventArgs e)
    {
        dg.CurrentPageIndex = e.NewPageIndex;
        BindGrid();
    }

//当单击某一行超级链接时，自动弹出新网页，调用程序test.aspx
protected void Page_Load(object sender, EventArgs e)
    {
        OleDbConnection Conn;
        Conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" +
            "Data Source=" + Server.MapPath("person.mdb"));
        Conn.Open();
        string strSQL = "select * from grade where 学号="+Request["id"];
        OleDbCommand Comm = new OleDbCommand(strSQL, Conn);
        OleDbDataReader dr = Comm.ExecuteReader();
        string html = " ";
        while (dr.Read())
        {
            html += "<h1>学员：";
            html += "<font color=red>"+dr["姓名"].ToString()+"</font>的成绩为：</h1><br>";
            html += "学号为："+dr["学号"].ToString()+"<br>";
            html += "数学成绩为："+dr["数学"].ToString()+"<br>";
            html += "";
        }
        Response.Write(html);
        Conn.Close();
    }

2、利用DataGrid控件动态添加数据

public partial class _Default : System.Web.UI.Page
{
    OleDbConnection Conn;
    protected void Page_Load(object sender, EventArgs e)
    {
        string Provider, DataBase, ConnStr, SQL;
        Provider = "Microsoft.Jet.OLEDB.4.0;";
        DataBase = Server.MapPath("person.mdb");
        ConnStr = "Provider=" + Provider + "Data Source=" + DataBase;
        Conn = new OleDbConnection(ConnStr);
        if (!IsPostBack) BindGrid();
    }

    private void BindGrid()
    {
        OleDbDataAdapter da = new OleDbDataAdapter("select * from grade", Conn);
        DataSet ds = new DataSet();
        da.Fill(ds);
        dg.DataSource = ds;
        dg.DataBind();
    }
    
    public void ChangePage(object sender, DataGridPageChangedEventArgs e)
    {
        dg.CurrentPageIndex = e.NewPageIndex;
        BindGrid();
    }

    public void Add_Click(object sender, EventArgs E)
    {
        String strSQL = "insert into grade values(" + id.Text + ",'" + sex.Text + "','" + name.Text + "'," + 
            yuwen.Text+","+math.Text+","+ english.Text+")";
        OleDbCommand Comm = new OleDbCommand(strSQL, Conn);
        Conn.Open();
        try
        {
            Comm.ExecuteNonQuery();
            Message.InnerHtml = "<b>添加成功</b>";
        }
        catch (OleDbException)
        {
            Message.InnerHtml = "添加失败";
            Message.Style["color"] = "red";
        }
        Conn.Close();
        BindGrid();
    }
}

<form id="form1" runat="server">
        <table width="95%">
            <tr>
                <td valign="top">
                    <asp:DataGrid ID="dg" runat="server" BorderColor="Black" CellPadding="3"
                        OnPageIndexChanged="ChangePage" PageSize="5" AutoGenerateColumns="False" BackColor="#CCCCFF" Font-Names="Verdana" Font-Size="9pt" Width="400px">
                        <PagerStyle HorizontalAlign="Right" NextPageText="后页" PrevPageText="前页" Mode="NumericPages" />
                        <HeaderStyle BackColor="#AAAADD" />
                        <Columns>
                            <asp:BoundColumn DataField="学号" HeaderText="学号" />
                            <asp:BoundColumn DataField="性别" HeaderText="性别" />
                            <asp:BoundColumn DataField="姓名" HeaderText="姓名" />
                            <asp:BoundColumn DataField="语文" HeaderText="语文" />
                            <asp:BoundColumn DataField="数学" HeaderText="数学" />
                            <asp:BoundColumn DataField="英语" HeaderText="英语" />
                        </Columns>
                    </asp:DataGrid>
                </td>
                <td valign="top">
                    <table style="font:8pt verdana">
                        <tr>
                            <td colspan="2" bgcolor="#aaaadd" style="font:10pt verdana">添加新的学员：
                            </td>
                        </tr>
                        <tr><td nowrap>学号：</td>
                        <td><asp:TextBox ID="id" runat="server" /></td>
                        </tr>
                        <tr><td nowrap>性别：</td>
                        <td><asp:TextBox ID="sex" runat="server" /></td>
                        </tr>
                        <tr><td nowrap>姓名：</td>
                        <td><asp:TextBox ID="name" runat="server" /></td>
                        </tr>
                        <tr><td nowrap>语文：</td>
                        <td><asp:TextBox ID="yuwen" runat="server" /></td>
                        </tr>
                        <tr><td nowrap>数学：</td>
                        <td><asp:TextBox ID="math" runat="server" /></td>
                        </tr>
                        <tr><td nowrap>英语：</td>
                        <td><asp:TextBox ID="english" runat="server" /></td>
                        </tr>
                        <tr><td colspan="2" style="padding-top:15" align="center">
                        <asp:Button Text="添加" OnClick="Add_Click" runat="Server" /></td>
                        </tr>
                        <tr><td colspan="2" style="padding-top:15" align="center">
                        <span id="Message" style="font:arial 11pt;" runat="server" /></td></tr>
                    </table>
                </td>
            </tr>
        </table>
    </form>

3、使用DataGrid控件动态操作数据

public partial class _Default : System.Web.UI.Page
{
    OleDbConnection Conn;
    protected void Page_Load(object sender, EventArgs e)
    {
        string Provider, DataBase, ConnStr;
        Provider = "Microsoft.Jet.OLEDB.4.0;";
        DataBase = Server.MapPath("person.mdb");
        ConnStr = "Provider=" + Provider + "Data Source=" + DataBase;
        Conn = new OleDbConnection(ConnStr);
        if (!IsPostBack) BindGrid();
    }

    private void BindGrid()
    {
        OleDbDataAdapter da = new OleDbDataAdapter("select * from grade order by 学号", Conn);
        DataSet ds = new DataSet();
        da.Fill(ds);
        dg.DataSource = ds;
        dg.DataBind();
    }

    public void DataGrid_Edit(object sender, DataGridCommandEventArgs e)
    {
        dg.EditItemIndex = (int)e.Item.ItemIndex;
        BindGrid();
    }

    public void DataGrid_Cancel(object sender, DataGridCommandEventArgs e)
    {
        dg.EditItemIndex = -1;
        BindGrid();
    }

    public void DataGrid_Update(object sender, DataGridCommandEventArgs e)
    {
        string strSQL = "update grade set " +
            "姓名='" + ((TextBox)e.Item.Cells[3].Controls[0]).Text
        + "',数学=" + ((TextBox)e.Item.Cells[4].Controls[0]).Text
        + " where 学号=" + dg.DataKeys[(int)e.Item.ItemIndex];
        OleDbCommand cm = new OleDbCommand(strSQL, Conn);
        Conn.Open();
        try
        {
            cm.ExecuteNonQuery();
            Message.InnerHtml = "<b>编辑成功</b>";
            dg.EditItemIndex = -1;
        }
        catch(OleDbException)
        {
            Message.InnerHtml="编辑失败";
            Message.Style["color"]="red";
        }
        cm.Connection.Close();
        BindGrid();
    }

    public void DataGrid_Delete(object sender, DataGridCommandEventArgs e)
    {
        string strSQL = "delete from grade where 学号="
        + dg.DataKeys[(int)e.Item.ItemIndex];
        OleDbCommand cm = new OleDbCommand(strSQL, Conn);
        Conn.Open();
        try
        {
            cm.ExecuteNonQuery();
            Message.InnerHtml = "<b>删除成功</b>";
        }
        catch (OleDbException)
        {
            Message.InnerHtml = "<b>删除失败</b>";
            Message.Style["color"]="red";
        }
        Conn.Close();
        BindGrid();
    }
}

<form id="form1" runat="server">
        <asp:DataGrid ID="dg" runat="server" Width="400" BackColor="#ccccff" BorderColor="black"
            ShowFooter="false" CellPadding="3" CellSpacing="0" Font-Name="Verdana" Font-Size="8pt"
            HeaderStyle-BackColor="#aaaadd" DataKeyField="学号" AutoGenerateColumns="false"
            OnEditCommand="DataGrid_Edit"
            OnCancelCommand="DataGrid_Cancel"
            OnUpdateCommand="DataGrid_Update"
            OnDeleteCommand="DataGrid_Delete">
            <Columns>
                <asp:EditCommandColumn EditText="编辑" CancelText="取消" UpdateText="更新" ItemStyle-Wrap="false" />
                <asp:ButtonColumn Text="删除" CommandName="Delete" ItemStyle-Wrap="false" />
                <asp:BoundColumn HeaderText="学号" DataField="学号" ReadOnly="true" />
                <asp:BoundColumn HeaderText="姓名" DataField="姓名" />
                <asp:BoundColumn HeaderText="数学" DataField="数学" />
            </Columns>
        </asp:DataGrid>
        <span id="Message" style="font:arial 11pt;" runat="Server" />
    </form>

程序中利用ItemStyle-Wrap="false"语句设置不折行显示，利用DataKeyField="学号"语句设置关键字段是学号，因此可以利用dg.DataKeys[(int)e.item.ItemIndex]取出某行的学号。取其行的其它列时，使用((TextBox)e.Item.Cells[3].Controls[0]).Text语句，e中存储当前的所有对象，通过表格和控件的定位，得到文本框的值。