问题描述
usingSystem;usingSystem.Data;usingSystem.Configuration;usingSystem.Collections;usingSystem.Web;usingSystem.Web.Security;usingSystem.Web.UI;usingSystem.Web.UI.WebControls;usingSystem.Web.UI.WebControls.WebParts;usingSystem.Web.UI.HtmlControls;usingSystem.Data.SqlClient;publicpartialclassimage_Detail:System.Web.UI.Page{stringsqlstr;DBdb=newDB();DataSetds=newDataSet();intPageSize;intCurrentPage;intRecordCount;intPageCount;protectedvoidPage_Load(objectsender,EventArgse){sqlstr="select*fromimage";//Response.Write(Request.QueryString.Get(0).ToString().Trim());//Label3.Text=Request.QueryString.Get(0).ToString().Trim();ds=db.GetDataTableBySql(sqlstr);if(ds.Tables[0].Rows.Count!=0){this.DataList1.DataSource=ds.Tables[0].DefaultView;this.DataList1.DataBind();}ViewState["CurrentPage"]=0;PageSize=3;sqlstr="select*fromimage";ds=db.GetDataTableBySql(sqlstr);if(ds.Tables[0].Rows.Count!=0){this.DataList1.DataSource=ds.Tables[0].DefaultView;this.DataList1.DataBind();}if(Page.IsPostBack==false){ViewState["PageIndex"]=0;sqlstr="selectcount(*)ascountfromimage";ds=db.GetDataTableBySql(sqlstr);if(ds.Tables[0].Rows.Count!=0){RecordCount=int.Parse(ds.Tables[0].Rows[0]["count"].ToString());}else{RecordCount=0;}if(RecordCount%PageSize==0){PageCount=RecordCount/PageSize;}else{PageCount=RecordCount/PageSize+1;}ViewState["PageCount"]=PageCount;this.Label2.Text=PageCount.ToString();//显示总页数BindList();}}privatevoidBindList(){intStartIndex=CurrentPage*PageSize;//设定导入的起始地址sqlstr="select*fromimage";SqlConnectioncon=newSqlConnection();con.ConnectionString=db.GetConnectionString();con.Open();SqlDataAdapterda=newSqlDataAdapter(sqlstr,con);da.Fill(ds,StartIndex,PageSize,"image");this.DataList1.DataSource=ds.Tables["image"].DefaultView;this.DataList1.DataBind();PageCount=(int)ViewState["PageCount"];//获得总页数this.ImageButton1.Enabled=true;this.ImageButton2.Enabled=true;if(CurrentPage==(PageCount-1))this.ImageButton2.Enabled=false;if(CurrentPage==0)this.ImageButton1.Enabled=false;this.Label1.Text=Convert.ToString(CurrentPage+1);}protectedvoidImageButton1_Click(objectsender,ImageClickEventArgse){CurrentPage=(int)ViewState["PageIndex"];//获得当前页索引CurrentPage=CurrentPage-1;ViewState["PageIndex"]=CurrentPage;BindList();}protectedvoidImageButton2_Click(objectsender,ImageClickEventArgse){CurrentPage=(int)ViewState["PageIndex"];//获得当前页索引CurrentPage=CurrentPage+1;ViewState["PageIndex"]=CurrentPage;BindList();}}[img=http://C:DocumentsandSettingsAdministrator桌面未命名][/img]
解决方案
解决方案二：
ds=db.GetDataTableBySql(sqlstr);ds是个DataSet，而GetDataTableBySql()方法返回DataTable看看db类中有没有返回DataSet的方法如果没有，直接定义一个DatatTable类型的变量dtdt=db.GetDataTableBySql(sqlstr);if(dt.Rows.Count!=0){...}
解决方案三：
在DB类里面定义么！DB类代码：usingSystem;usingSystem.Data;usingSystem.Configuration;usingSystem.Web;usingSystem.Web.Security;usingSystem.Web.UI;usingSystem.Web.UI.WebControls;usingSystem.Web.UI.WebControls.WebParts;usingSystem.Web.UI.HtmlControls;usingSystem.Data.SqlClient;///<summary>///DB的摘要说明///</summary>publicclassDB{publicSqlConnectionCon=newSqlConnection();publicSqlCommandCom=newSqlCommand();publicSqlDataAdapterDa=newSqlDataAdapter();publicDataSetDs=newDataSet();publicDB(){////TODO:在此处添加构造函数逻辑//}publicStringGetConnectionString(){StringConStr;ConStr=System.Configuration.ConfigurationManager.AppSettings.Get(0).ToString();returnConStr;}publicDataSetGetDataTableBySql(StringSqlStr){Con.ConnectionString=GetConnectionString();Com.Connection=Con;Com.CommandText=SqlStr;Da.SelectCommand=Com;try{Ds.Clear();Con.Open();Da.Fill(Ds);Con.Close();}catch(SqlException){Con.Close();}returnDs;}publicBooleanUpdateDataBySql(StringSqlStr){Con.ConnectionString=GetConnectionString();Com.Connection=Con;Com.CommandText=SqlStr;try{Con.Open();Com.ExecuteNonQuery();Con.Close();returntrue;}catch(Exception){Con.Close();returnfalse;}}}
解决方案四：
学会看提示，先判断table是否是nullif(ds.Tables.Count==0||ds.Tables[0].Rows.Count==0)return;
解决方案五：
支持楼上的，一般用ds的时候先判断ds为不为空然后里面的表为不为空，最后判断表里面的行为不为空最后才能放心的用这个里面的数据。。。如果在程序中不判断的话，一般会有bug
解决方案六：
“ds=db.GetDataTableBySql(sqlstr);”调试运行，先看看这个返回值是否正确。。。
解决方案七：
ds里是否有datetable？