public string SQL = "select * from Memorandum";
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ViewState["SQL"] = SQL;
BindData();
}
if (Request.QueryString["MId"] != null)
{
Delete(int.Parse(Request.QueryString["MId"].ToString()));
}
}
protected void AspNetPager1_PageChanged(object sender, EventArgs e)
{
BindData();
}
void BindData()
{
PagedDataSource pds = new PagedDataSource();
IList<MemorandumInfo> Infos = new DAL.Memorandum().GetAllMemorandumsBySQL(ViewState["SQL"].ToString());
pds.DataSource = Infos;
pds.AllowPaging = true;
pds.PageSize = 10;//取控件的分页大小
pds.CurrentPageIndex = this.AspNetPager1.CurrentPageIndex - 1;//显示当前页
//设置控件
this.AspNetPager1.RecordCount = Infos.Count;//记录总数
this.AspNetPager1.PageSize = 10;
Repeater1.DataSource = pds;
Repeater1.DataBind();
}
void Delete(int MId)
{
new Memorandum().DeleteMemorandum(MId);
Response.Write("<script>alert('成功删除该条备忘信息');location='?';</script>");
}
/// <summary>
/// 查询
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button1_Click(object sender, EventArgs e)
{
if (DropDownList1.SelectedValue == "0")
{
ViewState["SQL"] = "select * from Memorandum";
BindData();
}
else
{
ViewState["SQL"] = "SELECT MId, MemoTitle, MemoContent, MemoStartTime, MemoEndTime FROM Memorandum WHERE (MemoEndTime - NOW() <=7)";
BindData();
}
}
}
|
ViewState 用来跟踪和保存控件的状态信息。否则这些信息可能会丢失，原因可能是这些值不随着 form 回发，或者根本就不在 page 的 html 中。
ViewState 中保存着代码中改变的控件属性，通过代码绑定到控件的任何数据，以及由用户操作触发，回发的任何更改。
ViewState 还提供了一个状态包(StateBag), 这是一个特殊的集合或字典(collection or dictionary), 可以用来保存，通过一个 key 来恢复任意的对象或者值。
赋值：ViewState[key] = value;
取值：value = ViewState[key];