很久都没有写一点东西了,最近一直在学习.net,前两天看到椰子林写的一篇《ASP.NET分页组件学与用》,于是自己就跟着做了一遍,一次成功,在此向他表示感谢,也向他那种共享的精神致敬!可是后来我发觉这个组件用起来有点麻烦,在Page_Load里面不但要得到记录集,还要写SQL语句分页,最后还要自己写代码将包含数据的<table></table>输出到客户端,于是我就想呀要是可以像DataGrid那样只是简单的绑定一下就可以用就好,分页,显示数据呀这些都交给组件去完成,正是这灵光一现,我就开始冲动了,没办法程序就是有这么大的魅力!结果,我昨天晚上失眠了,哎!冲动的惩罚呀!今天早上,我带着红肿的眼睛走进了机房,开始实现我昨天晚上梦见的那个东东,幸运的是--我实现了,呵呵,一个字爽!忘了告诉大家,我还是一个学生,做出来我很高兴了,技巧谈不上,高手们看了莫怪。下面我把基本的做法说一下!
如何做自定义控件,以及如何实现分页在这里我就不多说了,大家可以看一下椰子林写的相关文章,我要说说我的做法:
首先定义一个DataSource属性,如下:
private DataTable dt; //数据源
/// <summary> /// 数据源 /// </summary> public DataTable DataSource { get { return dt; } set { if (value == null) throw new Exception("数据源不可为空"); else dt = value; } } 该属性用于接受前端传进来的DataTable对象。我们可以在前端使用ADO.NET获得数据并将数据填充到一个DataTable中,再将此包含数据的DataTable赋于组件的DataSource属性,接下来的工作就是由组件向客户端输出包含数据的<table></table>标签了,怎么样简单吧!其实没有做多少改进,只是简单的扩展了一下,如下:
/// <summary> /// 创建数据表 /// </summary> /// <returns>表格的Html表示字符串</returns> protected string CreateDataTable() { string table = null; //表格,显示了所有的字段和记录 string tableHead = null; // 表头用于显示字段名的<tr> string tdHead = null; // 表头用于显示字段名的<td>包含在tableHead中 string tableBody = null; // 表主体用于显示记录的<tr> // 为了实现分页定义min和max两个变量 // min代表从那一条记录开始显示 // max代表到那一条记录结束 // 如果当前是第2页每页显示10条记录的话,那么min的值就是10,max的值就是20 int min = 0; int max = 0; // for循环用于产生表头,即字段名 for (int i = 0; i < this.dt.Columns.Count; i++) { tdHead = tdHead + "<td>" + this.dt.Columns[i].ColumnName + "</td>"; } // 判断当前页是否最后一页 if (this.currentpage == this.PageCount) { min = (this.currentpage - 1) * this.count; max = this.dt.Rows.Count; } else { min = (this.currentpage - 1) * this.count; max = this.currentpage * this.count; } // for循环用于产生表主体,即提取记录 for (int j = min; j < max; j++) { tableBody = tableBody + "<tr bgcolor='#FFFFFF'>";
for (int k = 0; k < this.dt.Columns.Count; k++) { tableBody = tableBody + "<td>" + this.dt.Rows[j][k].ToString() + "</td>"; } tableBody = tableBody + "</tr>"; }
tableHead = "<tr bgcolor='#FFFFFF'>" + tdHead + "</tr>";
table = "<table border='0' cellpadding='0' cellspacing='1' width='100%' height='100%' bgcolor='#000000' style='font-size:9pt'>" + tableHead + tableBody + "</table>"; return table; }
这样就得到了包含数据的表格的Html字符串,跟着就是做分页部分,最后重写Render(HtmlTextWriter output)方法将整个组件输出到客户端!这里我不一一详述步骤,我把代码帖出来,有兴趣的可以将代码拷贝到本机上运行一下!
组件源代码如下:(调试通过)
public class MyDataGrid : System.Web.UI.WebControls.WebControl { private int currentpage; //当前页 private int count; //每页显示的记录条数 private int navigcount; //导航连接的个数 private DataTable dt; //数据源
private const string SCRIPTSTRING = "<script language='javascript'>\n" + " function go(ctrl,max)\n" + "{\n" + "if(ctrl.value >= 1 && ctrl.value <= max)\n" + "{\n" + "var url;\n" + "var index;\n" + "url = location.href;\n" + "index = url.indexOf('?');\n" + "if(index == -1)\n" + "{\n" + "}\n" + "else\n" + "{\n" + "url = url.substring(0,index);\n" + "}\n" + "location.href = url + '?CurrentPage=' + ctrl.value;\n" + "}\n" + "else\n" + "{\n" + "alert('您输入的页码必须是符合页面要求的数字,最大值是:' + max);\n" + "return false;\n" + "}\n" + "}\n" + "</script>\n"; /// <summary> /// 当前页 /// </summary> public int CurrentPage { get { return currentpage; } set { if (value <= 0) currentpage = 1; else currentpage = value; } } /// <summary> /// 每页显示的记录条数 /// </summary> public int Count { get { return count; } set { if (value <= 0) count = 10; else count = value; } } /// <summary> /// 导航连接的个数 /// </summary> public int NavigCount { get { return navigcount; } set { if (value <= 0) navigcount = 10; else navigcount = value; } } /// <summary> /// 总页数 /// </summary> public int PageCount { get { if (this.dt.Rows.Count % count > 0) return ((int)this.dt.Rows.Count / count) + 1; else return ((int)this.dt.Rows.Count / count); } }
/// <summary> /// 数据源 /// </summary> public DataTable DataSource { get { return dt; } set { if (value == null) throw new Exception("数据源不可为空"); else dt = value; } } protected override void Render(HtmlTextWriter output) { string Table = CreateDataTable(); string PageControl = CreatePageControl();
string Result = string.Format("<table border='0' cellpadding='0' cellspacing='1' width='724' height='93' bgcolor='#000000' style='font-size: 9pt'>\n" + "<tr bgcolor='#FFFFFF'>\n" + "<td width='724' height='68' valign='top'>{0}</td>\n" + "</tr>\n" + "<tr bgcolor='#FFFFFF'>\n" + "<td width='724' height='25' valign='top'>{1}</td>\n" + "</tr>\n" + "</table>\n",Table.ToString(),PageControl.ToString()); output.Write(Result.ToString()); } /// <summary> /// 创建数据表 /// </summary> /// <returns>表格的Html表示字符串</returns> protected string CreateDataTable() { string table = null; //表格,显示了所有的字段和记录 string tableHead = null; // 表头用于显示字段名的<tr> string tdHead = null; // 表头用于显示字段名的<td>包含在tableHead中 string tableBody = null; // 表主体用于显示记录的<tr> // 为了实现分页定义min和max两个变量 // min代表从那一条记录开始显示 // max代表到那一条记录结束 // 如果当前是第2页每页显示10条记录的话,那么min的值就是10,max的值就是20 int min = 0; int max = 0; // for循环用于产生表头,即字段名 for (int i = 0; i < this.dt.Columns.Count; i++) { tdHead = tdHead + "<td>" + this.dt.Columns[i].ColumnName + "</td>"; } // 判断当前页是否最后一页 if (this.currentpage == this.PageCount) { min = (this.currentpage - 1) * this.count; max = this.dt.Rows.Count; } else { min = (this.currentpage - 1) * this.count; max = this.currentpage * this.count; } // for循环用于产生表主体,即提取记录 for (int j = min; j < max; j++) { tableBody = tableBody + "<tr bgcolor='#FFFFFF'>";
for (int k = 0; k < this.dt.Columns.Count; k++) { tableBody = tableBody + "<td>" + this.dt.Rows[j][k].ToString() + "</td>"; } tableBody = tableBody + "</tr>"; }
tableHead = "<tr bgcolor='#FFFFFF'>" + tdHead + "</tr>";
table = "<table border='0' cellpadding='0' cellspacing='1' width='100%' height='100%' bgcolor='#000000' style='font-size:9pt'>" + tableHead + tableBody + "</table>"; return table; }
/// <summary> /// 创建分页控件 /// </summary> /// <returns>返回分页控件的Html表示字符串</returns> protected string CreatePageControl() { string leftInfo = string.Format("页:{0}/{1}"+"  "+"每页{2}条"+"  "+"共{3}条", this.CurrentPage.ToString(),this.PageCount.ToString(),this.Count.ToString(),this.dt.Rows.Count.ToString()); int min = 0; int max = 0;
if (this.CurrentPage > this.PageCount) { this.CurrentPage = this.PageCount; }
if (this.CurrentPage % this.Count == 0) { min = this.CurrentPage + 1; max = this.CurrentPage + this.Count; } else if (this.CurrentPage % this.Count == 1&& this.CurrentPage > this.Count) { min = (((int)this.CurrentPage / this.Count) - 1) * this.Count + 1; max = this.CurrentPage - 1; } else { min = ((int)this.CurrentPage / this.Count) * this.Count + 1; max = (((int)this.CurrentPage / this.Count) + 1) * this.Count; }
string numberStr = " "; string url = this.Context.Request.Url.ToString();
if (url.IndexOf("?") == -1) { } else { url = url.Substring(0,url.IndexOf("?")); }
for (int i = min; i <= max; i++) { if (i <= this.PageCount) { if (i == this.CurrentPage) { numberStr = numberStr + "<a href=" + url + "?CurrentPage=" + i.ToString() + ">" + "<I style='color:red'>" + i.ToString() + "</I>" +"</a>" + "\n"; } else { numberStr = numberStr + "<a href=" + url + "?CurrentPage=" + i.ToString() + ">" + i.ToString() +"</a>" + "\n"; } } }
string first,prev,next,last; first = url + "?CurrentPage=" + 1; if (this.CurrentPage == 1) { prev = url + "?CurrentPage=1"; } else { prev = url + "?CurrentPage=" + (this.CurrentPage - 1).ToString(); }
if (this.CurrentPage == this.PageCount) { next = url + "?CurrentPage="+ this.PageCount; } else { next = url + "?CurrentPage=" + (this.CurrentPage + 1).ToString(); }
last = url + "?CurrentPage=" + this.PageCount;
string centerInfo = string.Format("<font face='Webdings' style='font-size:14px'><a href={0}>7</a><a href={1}>3</a></font>{2}<font face='Webdings' style='font-size:14px'><a href={3}>4</a><a href={4}>8</a></font>",first,prev,numberStr,next,last);
string result = string.Format("<table border='0' cellpadding='0' cellspacing='0' width='100%' style='font-size:9pt'>\n" + "<tr><td width='25%' align='left'>{0}</td>\n" + "<td width='61%' align='right'>{1}</td>" + "<td width='14%' align='right'><input type='text' name='T1' size='4' style='border-bottom:solid 1pt gray;border-top :solid 1pt gray; border-left:solid 1pt gray;border-right:solid 1pt gray;'> \n <input type='button' name='B1' size='6' value=go style='border-bottom:solid 1pt gray;border-top :solid 1pt gray; border-left:solid 1pt gray;border-right:solid 1pt gray;' onclick='go(T1,{2})'></td>\n" + "</tr></table>",leftInfo,centerInfo,this.PageCount); return result; }
protected override void OnPreRender(EventArgs e) { base.OnPreRender (e); if(!Page.IsClientScriptBlockRegistered("WEREW-332DFAF-FDAFDSFDSAFD")) { Page.RegisterClientScriptBlock("WEREW-332DFAF-FDAFDSFDSAFD",SCRIPTSTRING); } } }
测试工程代码:
public class TestMyDataGrid : System.Web.UI.Page { protected myControlLibrary.MyDataGrid MyDataGrid1; private void Page_Load(object sender, System.EventArgs e) { // 在此处放置用户代码以初始化页面 int currentpage; if (this.Request.Params["CurrentPage"] == null) { currentpage = 1; } else { currentpage = Convert.ToInt32(this.Request.Params["CurrentPage"].ToString()); }
this.MyDataGrid1.CurrentPage = currentpage; this.MyDataGrid1.Count = 10; this.MyDataGrid1.NavigCount = 10;
SqlConnection conn = new SqlConnection("server=localhost; database=NorthWind; uid=sa"); SqlCommand cmd = new SqlCommand("select * from [Order Details]",conn); SqlDataAdapter da = new SqlDataAdapter(); da.SelectCommand = cmd; DataSet ds = new DataSet();
conn.Open(); da.Fill(ds,"table"); conn.Close();
this.MyDataGrid1.DataSource = ds.Tables["table"]; }
#region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN:该调用是 ASP.NET Web 窗体设计器所必需的。 // InitializeComponent(); base.OnInit(e); } /// <summary> /// 设计器支持所需的方法 - 不要使用代码编辑器修改 /// 此方法的内容。 /// </summary> private void InitializeComponent() { this.Load += new System.EventHandler(this.Page_Load);
} #endregion }
页面版排的不好,只好劳动一下你,呵呵! 
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