我正在尝试在onClick上添加一个新行。但是,它取代了我现有的添加到新行的行。
以下是代码:
Main.cs
protected void Button1_Click(object sender, EventArgs e)
{
DateTime selectedDate = CalendarMain.SelectedDate;
string SportType = ddlSportType.SelectedItem.ToString();
string distance = ddlDistance.SelectedItem.ToString();
plan wp = new plan();
wp.Time_Start = selectedDate;
wp.Duration = distance;
wp.Activity = SportType;
DataTable dt = wp.addPlanDetailDataRow();
gvActivityList.DataSource = dt;
gvActivityList.DataBind();
}
plan.cs
public DataTable addPlanDetailDataRow()
{
DataTable dt = new DataTable();
dt.Columns.Add("Activity");
dt.Columns.Add("Duration");
dt.Columns.Add("status");
dt.Columns.Add("Time_Start");
dt.Columns.Add("Plan_ID");
DataRow newRow = dt.NewRow();
dt.Rows.Add(newRow);
return dt;
}
我不确定我错过了什么。请指导我的错误。非常感谢
答案 0 :(得分:5)
您的DataTable在addPlanDetailDataRow
本地定义。它应该在类范围中定义,并且 instanstiated 一次以保留先前的值。以某种方法在datatable中添加for列,以便调用一次。
DataTable dt = new DataTable();
private InitDataTable() //This method should be called once
{
dt.Columns.Add("Activity");
dt.Columns.Add("Duration");
dt.Columns.Add("status");
dt.Columns.Add("Time_Start");
dt.Columns.Add("Plan_ID");
}
public DataTable addPlanDetailDataRow()
{
DataRow newRow = dt.NewRow();
dt.Rows.Add(newRow);
return dt;
}
修改强>
由于DataTable被声明为数据成员并且可以被类的所有方法访问,因此您不需要返回数据表。这将更改addPlanDetailDataRow,如下所示。另请注意,您只是添加行但不填充行。
public void addPlanDetailDataRow()
DataRow newRow = dt.NewRow();
newRow["Activity"] = "a1"; //These dummy values should be replaced by real values.
newRow["Duration"] = "d1";
newRow["status"] = "s1";
newRow["Time_Start"] = "st1";
newRow["Plan_ID"] = "p1";
dt.Rows.Add(newRow);
}
调用方法
gvActivityList.DataSource = addPlanDetailDataRow();
gvActivityList.DataBind();
正如DataBind在asp.net中使用的那样,您可能需要将DataTable放在ViewState中或将数据放在DataBase中。
答案 1 :(得分:3)
使用ViewState记住以前的值:
编辑: -
protected void Button1_Click(object sender, EventArgs e)
{
DateTime selectedDate = CalendarMain.SelectedDate;
string SportType = ddlSportType.SelectedItem.ToString();
string distance = ddlDistance.SelectedItem.ToString();
plan wp = new plan();
wp.Time_Start = selectedDate;
wp.Duration = distance;
wp.Activity = SportType;
DataTable dt = new DataTable();
dt.Columns.Add("Activity");
dt.Columns.Add("Duration");
dt.Columns.Add("status");
dt.Columns.Add("Time_Start");
dt.Columns.Add("Plan_ID");
DataTable dt1 = wp.addPlanDetailDataRow(dt);
gvActivityList.DataSource = dt;
gvActivityList.DataBind();
}
public DataTable addPlanDetailDataRow(DataTable dt)
{
if (ViewState["Datatable"] != null)
{
dt = (DataTable)ViewState["Datatable"];
}
ViewState["Datatable"] = dt;
DataRow dr = dt.NewRow();
dr["Activity"]="value1";
dr["Duration"]="value2";
dr["status"]="value3";
dr["Time_Start"]="value4";
dr["Plan_ID"]="value5";
dt.Rows.Add(dr);
return dt;
}
答案 2 :(得分:1)
我已经尝试了一个示例页面,其工作原理见下面的代码。
//在PostBack尝试将数据表放入Viewstate并查看
的大小后保留数据// Viewstate,启用跟踪。如果它不是太大而且小于1 MB,那么使用Viewstate,
//因为它效率更高,不使用任何服务器资源。
Main.cs
protected void btn1_Click(object sender, EventArgs e)
{
DateTime selectedDate = DateTime.Now;
string SportType = "Dummy SportType";
string distance = "Dymmy distance";
plan wp = new plan();
wp.Time_Start = selectedDate;
wp.Duration = distance;
wp.Activity = SportType;
DataTable dt;
if (ViewState["Datatable"] != null) //
{
wp.dt = (DataTable)ViewState["Datatable"];
}
else
{
wp.InitDataTable();
}
dt = wp.addPlanDetailDataRow();
ViewState["Datatable"] = dt;
gvActivityList.DataSource = dt;
gvActivityList.DataBind();
}
plan.cs
public plan()
{
//
// TODO: Add constructor logic here
//
}
public DataTable dt;
public void InitDataTable()
{
dt = new DataTable();
dt.Columns.Add("Activity");
dt.Columns.Add("Duration");
dt.Columns.Add("status");
dt.Columns.Add("Time_Start");
dt.Columns.Add("Plan_ID");
}
public DateTime Time_Start;
public string Duration;
public string Activity;
public DataTable addPlanDetailDataRow()
{
DataRow newRow = dt.NewRow();
newRow["Activity"] = this.Activity;
newRow["Duration"] = this.Duration;
newRow["status"] = "s1";
newRow["Time_Start"] = this.Time_Start;
newRow["Plan_ID"] = "p1";
dt.Rows.Add(newRow);
return dt;
}