前言：

　　在某次公司面试时被问到对GridView操作的熟悉程度，在那之前一直用Repeater内嵌table标签对GridView操作确实很 少，于是最近在项目的后台上对GridView进行了一番实操，本文和后面的另一篇GridView实战二：使用ObjectDataSource数据源 控件均是这段时间的一些总结。

　　GridView优点就是集数据绑定、分页、排序、删、改于一身，提高了开发效率；缺点嘛，就是运行效率低，并且它本身不带添加功能。于是GridView用于后台开发是一个不错的选择，而前台页面还是少用为妙咯。

实战一：

　　1.本次实战效果图如下：

图一.展示状态

图二.编辑状态

图三.添加记录状态

2.具体代码

.aspx页面

                 
                 
                     
                          
                           
                               
                                
                            
                           
       
        <%#Eval("Name") %>
                           
                               
                                 
                                
                                
                                
                             
                       
                       
                          
                           
                               
                                
                             
                            
                               
                                
                            
                            
                                
                                 
                            
                        
                      
                          
                           
                               
                                
                            
                            
       
        <%#Eval("Country")%>
                            
                               
                            
                        
                      
                          
                           
       
        Hobby
                           
       
        <%#Eval("Hobby") %>
                            
                               
                                
                            
                       
                      
                          
                           
                               
                                
                            
                           
                               
                                 
                            
                           
                               
                                 
                            
                        
                  
                 
                 
                 
                     
      
                           当前第<%#this.gv.PageIndex+1 %>/<%#this.gv.PageCount %>页                
      
                
      
       页
      
                
      
                    
                           
                       
      
                
      
       跳转到第
      
            
                 
                     
      
       Name:                    
                           
                           
                          
                           
                        
      
                
      
       Sex:                    
                               
                                
                            
                       
      
                
      
       Country:                    
                           
                           
                           
                       
      
                
      
       Hobby:                    
                           
                       
      
                
      
                    
                           
                       
      
            
              
    

说明：

1.显示状态时：对于只显示文字串的用<%#Eval("字段名")%>直接绑定，而对于单选组（性别）的内容就放在GridView的OnRowDataBound来绑定。

2.编辑状态时：复选组、单选组合下拉列表都在OnRowDataBound来绑定；这里没有用数据源控件，所以用<%#Bind("字段 名")%>和<%#Eval("字段名")%>没区别，<%#Bind("字段名")%>的双向通讯不起作用。

3.新增状态：因为GridView自身附带新增记录的功能，所以选择在EmptyDataTemplate中实现新增的功能（借鉴其他同行的做法！）；因为使用了验证控件，所以把取消按钮（操作不验证合法性）设为不触发验证。

4.分页功能：本例是将分页功能放置到gridview的PagerTemplate中实现。这里有两个注意点：

a.DropDownList设置AutoPostBack为true；

b.因为要触发DropDownList的OnSelectedIndexChanged事件，所以viewstate要启用。触发 OnSelectedIndexChanged事件的条件是postback的selectedIndex和原始值不同，当viewstate启用时原始 值就是viewstate中保存的值，当viewstate禁用时就是控件初始化时的selectedIndex或第一个选项。因此如果禁用了 ViewState那么当选择回控件初始化时的选项时就不会触发OnSelectedIndexChanged事件了。

c.GridView的OnRowDataBound中每次postback都重新初始化DropDownList。因为DropDownList 包含在GridView中是动态生成的，当PostBack时GridView并不会恢复其中的动态内容；如果把分页功能放在GridView以外实现， 那么动态生成的时DropDownList的选项，就Postback时不用再初始化了。

d.因为DropDownList位于GridView里面，所以当把某个ListItem的enable设为false时，该选项就不生成（连 Html代码都没了），如果放在GridView外只是显示为不可用而已，原因不明。为实现添加状态初始画面中存在默认不可选的listitem效果，用 了html的disabled属性来设置。

.aspx.cs代码

public partial class _Default : System.Web.UI.Page {    private DataManager dm = new DataManager();    protected void Page_Load(object sender, EventArgs e)    {        if (!IsPostBack)        {            this.gv.DataSource = dm.GetDt();            this.gv.DataBind();            //记录最近一次排序方向            ViewState["Direction"] = SortDirection.Descending;        }    }    protected void gv_OnRowDataBound(object sender, GridViewRowEventArgs e)    {        DataRowView drv = e.Row.DataItem as DataRowView;        if (e.Row.RowType == DataControlRowType.DataRow)        {            //显示时            if (this.gv.EditIndex == -1)            {                //设置性别                RadioButtonList rbl = e.Row.FindControl("rblSexShow") as RadioButtonList;                rbl.Items.Add(new ListItem("Male", "M"));                rbl.Items.Add(new ListItem("Female", "F"));                if ((drv["Sex"] as string).ToLower().Equals("m"))                    rbl.Items[0].Selected = true;                else                    rbl.Items[1].Selected = true;            }             //修改时：            else if(e.Row.RowIndex == this.gv.EditIndex)            {                //性别                RadioButtonList rbl = e.Row.FindControl("rblSexEdit") as RadioButtonList;                rbl.Items.Add(new ListItem("Male", "M"));                rbl.Items.Add(new ListItem("Female", "F"));                if ((drv["Sex"] as string).ToLower().Equals("m"))                    rbl.Items[0].Selected = true;                else                    rbl.Items[1].Selected = true;                //国籍                DropDownList ddlCountry = e.Row.FindControl("ddlCountry") as DropDownList;                DataTable countryDt = dm.GetCountry();                ListItem li = null;                for(int i=0;i
    
     =0)                        hobbyLi.Selected = true;                    cbl.Items.Add(hobbyLi);                }            }        }        else if (e.Row.RowType == DataControlRowType.Pager)        {            //绑定分页控件            DropDownList ddlPaging = e.Row.FindControl("ddlPaging") as DropDownList;            for (int i = 0; i < this.gv.PageCount; i++)            {                ddlPaging.Items.Add(new ListItem(Convert.ToString(i + 1), Convert.ToString(i)));            }            ddlPaging.SelectedIndex = this.gv.PageIndex;        }        else if (e.Row.RowType == DataControlRowType.EmptyDataRow)        {            //添加记录画面//国籍            DropDownList ddlCountry = e.Row.FindControl("ddlCountry") as DropDownList;            DataTable countryDt = dm.GetCountry();            ListItem li =  new ListItem("Please Select","");            li.Attributes["disabled"] = "disabled";            li.Selected = true;            ddlCountry.Items.Add(li);            for (int i = 0; i < countryDt.Rows.Count; ++i)            {                string cn = countryDt.Rows[i]["cn"] as string;                li = new ListItem(cn, cn);                ddlCountry.Items.Add(li);            }            //兴趣            CheckBoxList cbl = e.Row.FindControl("cbxlHobby") as CheckBoxList;            DataTable hobbyDt = dm.GetHobby();            ListItem hobbyLi = null;            string hstr = string.Empty;            for (int i = 0; i < hobbyDt.Rows.Count; i++)            {                hstr = hobbyDt.Rows[i]["hobby"] as string;                hobbyLi = new ListItem(hstr, hstr);                cbl.Items.Add(hobbyLi);            }        }    }    /// 
     
/// 分页控件的OnSelectedIndexChanged/// 
/// 
     /// 
         protected void ddlPaging_OnSelectedIndexChanged(object sender, EventArgs e)    {        this.gv.PageIndex = (sender as DropDownList).SelectedIndex;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 删除记录/// 
/// 
     /// 
         protected void gv_OnRowDeleting(object sender, GridViewDeleteEventArgs e)    {        dm.DelRecord(Convert.ToInt32(this.gv.DataKeys[e.RowIndex].Value));        this.gv.PageIndex = 0;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 修改记录/// 
/// 
     /// 
         protected void gv_OnRowEditing(object sender, GridViewEditEventArgs e)    {        this.gv.EditIndex = e.NewEditIndex;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 取消修改/// 
/// 
     /// 
         protected void gv_OnRowCancelingEdit(object sender, GridViewCancelEditEventArgs e)    {        this.gv.EditIndex = -1;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 更新记录/// 
/// 
     /// 
         protected void gv_OnRowUpdating(object sender, GridViewUpdateEventArgs e)    {        GridViewRow gvr = this.gv.Rows[e.RowIndex];        int id = Convert.ToInt32(this.gv.DataKeys[e.RowIndex].Value);        string name = (gvr.Cells[0].FindControl("tbxName") as TextBox).Text;        string sex = (gvr.Cells[1].FindControl("rblSexEdit") as RadioButtonList).SelectedValue;        string country = (gvr.Cells[2].FindControl("ddlCountry") as DropDownList).SelectedValue;        System.Text.StringBuilder hobbys = new System.Text.StringBuilder();        foreach (ListItem li in (gvr.Cells[3].FindControl("cbxlHobby") as CheckBoxList).Items)        {            if (li.Selected)                hobbys.Append(li.Value+",");        }        if (hobbys.Length >= 2)            hobbys.Remove(hobbys.Length - 1, 1);        dm.UpdateRecord(id, name, country, sex, hobbys.ToString());        this.gv.EditIndex = -1;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 提交新记录/// 
/// 
     /// 
         protected void lbtnSubmit_OnClick(object sender, EventArgs e)    {        LinkButton lbtnSubmit = sender as LinkButton;        GridViewRow tr = lbtnSubmit.NamingContainer as GridViewRow;        string name = (tr.Cells[0].FindControl("tbxName") as TextBox).Text;        string sex = (tr.Cells[0].FindControl("rblSex") as RadioButtonList).SelectedValue;        string country = (tr.Cells[0].FindControl("ddlCountry") as DropDownList).SelectedValue;        System.Text.StringBuilder hobbys = new System.Text.StringBuilder();        foreach (ListItem li in (tr.Cells[0].FindControl("cbxlHobby") as CheckBoxList).Items)        {            if (li.Selected)                hobbys.Append(li.Value + ",");        }        if (hobbys.Length >= 2)            hobbys.Remove(hobbys.Length - 1, 1);        dm.AddRecord(name,country,sex,hobbys.ToString());        this.gv.PageIndex = 0;        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 退出添加新记录/// 
/// 
     /// 
         protected void lbtnCancel_OnClick(object sender, EventArgs e)    {        this.gv.DataSource = dm.GetDt();        this.gv.DataBind();    }    /// 
     
/// 显示添加画面/// 
/// 
     /// 
         protected void lbtnShowAdd_OnClick(object sender, EventArgs e)    {        this.gv.DataSource = null;        this.gv.DataBind();    }    /// 
     
/// 排序/// 
/// 
     /// 
         protected void gv_OnSorting(object sender, GridViewSortEventArgs e)    {        DataTable dt = dm.GetDt();        string direction = string.Empty;        if (e.SortDirection == (SortDirection)Enum.Parse(typeof(SortDirection),Convert.ToString(ViewState["Direction"])))            direction = "asc";        else            direction = "desc";        dt.DefaultView.Sort = string.Format("{0} {1}", e.SortExpression, direction);        ViewState["Direction"] = (direction.Equals("asc") ? SortDirection.Descending : SortDirection.Ascending);        this.gv.DataSource = dt;        this.gv.DataBind();    }}
    

说明：

1.显示、编辑、新增时数据绑定都集中在gv_OnRowDataBound方法中，通过e.Row.RowType来分别处理。

2.排序：通过DataTable.DefaultView来实现，用一个ViewState变量存放最近一次的排序方向的反方向，来使每次排序的方向都不同。GridView的SortDirection为只读属性，所以别指望设定它来实现排序哦！

3.modify、update、delete和cancel按钮的实现利用GridView预设的CommandName来处理

当然也可以自己写OnCommand的处理代码来处理，就是烦一点。

数据操作类：

public class DataManager{    private static DataTable dt = null;//用户记录    private static DataTable countryDt = null;//国籍    private static DataTable hobbyDt = null;//兴趣    public DataManager()    {        if (dt == null)        {            dt = new DataTable();            dt.Columns.Add("ID");            dt.Columns.Add("Name");            dt.Columns.Add("Sex");            dt.Columns.Add("Country");            dt.Columns.Add("Hobby");            //Default Data            dt.Rows.Add(new object[] { 1,"Mary","F","China","Cooking,Music"});            dt.Rows.Add(new object[] { 2, "John", "M", "China", "Tennis" });        }        if (countryDt == null)        {            countryDt=new DataTable();            countryDt.Columns.Add("cn");                        //Default Data            countryDt.Rows.Add(new object[] { "China" });            countryDt.Rows.Add(new object[] { "French" });            countryDt.Rows.Add(new object[] { "America" });            countryDt.Rows.Add(new object[] { "Afria" });            countryDt.Rows.Add(new object[] { "Japan" });        }        if (hobbyDt == null)        {            hobbyDt = new DataTable();            hobbyDt.Columns.Add("hobby");            //Default Data            hobbyDt.Rows.Add(new object[] { "Cooking" });            hobbyDt.Rows.Add(new object[] { "Music" });            hobbyDt.Rows.Add(new object[] { "Reading" });            hobbyDt.Rows.Add(new object[] { "Movies" });            hobbyDt.Rows.Add(new object[] { "Tennis" });        }    }    public DataTable GetDt()    {        return dt;    }    public bool DelRecord(int id)    {        DataRow[] drs = dt.Select("ID=" + id);        bool result = false;        if (drs.Length == 1)        {            dt.Rows.Remove(drs[0]);            result = true;        }        return result;    }    public bool UpdateRecord(int id, string name, string country, string sex, string hobby)    {        DataRow[] drs = dt.Select("ID=" + id);        bool result = false;        if (drs.Length == 1)        {            drs[0]["Name"] = name;            drs[0]["Country"] = country;            drs[0]["Hobby"] = hobby;            drs[0]["Sex"] = sex;            result = true;        }        return result;    }    public bool AddRecord(string name, string country, string sex, string hobby)    {        DataRow[] drs = dt.Select();        Array.Sort
    
     (drs, new Comparison
     
      (SortHandler));        int newId = 1+Convert.ToInt32(drs[0]["ID"]);        dt.Rows.Add(new object[] {newId,name,sex,country,hobby });        return true;    }    private int SortHandler(DataRow arg1, DataRow arg2)    {        if (Convert.ToInt32(arg1["ID"]) == Convert.ToInt32(arg2["ID"]))            return 0;        else if (Convert.ToInt32(arg1["ID"]) < Convert.ToInt32(arg2["ID"]))            return 1;        else            return -1;    }    public DataTable GetCountry()    {        return countryDt;    }    public DataTable GetHobby()    {        return hobbyDt;    }}
     
    

这里没什么好说的，就是AddRecord方法中用到了Array.Sort方法，这个方法我用得很少，不过觉得挺好用的，定义一个方法作为第二个参数传入就可以了。

总结：

　　不适用数据源控件的优点是，新增记录时可以马上看到新增的记录；缺点是即使实现了分页功能，但每次还是从数据库中读取全部数据，效率低。而使用 ObejctDataSource来绑定就可以解决从数据库读取全部数据的问题，并且附带数据缓存（应用程序级缓存）的功能，省心多了。但却又因 ObjectDataSource不支持重新绑定，而使新增记录时不能马上看到新增的记录的缺点。

　　关于ObjectDataSource配合GridView的使用将在《GridView实战二：使用ObjectDataSource数据源控件》讲述。