如何在GridView中允许排序
本文关键字：排序 许排序 GridView | 更新日期: 2023-09-27 18:11:01
我有以下GirdView，它显示了一些文件的修改日期:
<asp:GridView ID="GridView1" AllowSorting="true" OnSorting="GridView1_Sorting" ClientIDMode="Static" runat="server" AutoGenerateColumns="false" EmptyDataText="No PDF was generated">
<Columns>
<asp:BoundField DataField="Text" HeaderText="File Name" SortExpression="FileName" />
<asp:BoundField DataField="Value" HeaderText="File Date" SortExpression="FileDate" />
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lnkDownload" Text="Download" runat="server"
CommandArgument='<%# Container.DataItemIndex %>'
OnClick="DownloadFile" />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lnkView" Text="View in Browser"
CommandArgument='<%# Container.DataItemIndex %>'
OnClientClick="window.document.forms[0].target='blank';"
runat="server" OnClick="ViewFile" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
我正在用以下代码填充GridView:
if (!Page.IsPostBack)
{
BindData();
//MessageBox.Show(files.Count() + ""); // displays the count for the files being displayed
}
protected void BindData()
{
try
{
filePaths = Directory.GetFiles(@"C:'PDFGenerate");
files = new List<ListItem>();
foreach (string filePath in filePaths)
{
files.Add(new ListItem(Path.GetFileName(filePath), File.GetLastWriteTime(filePath).ToString()));
}
GridView1.DataSource = files;
GridView1.DataBind();
Session["fileData"] = files;
}
catch (Exception ce)
{
}
//MessageBox.Show(files.Count() + ""); // displays the count for the files being displayed
}
我允许在GridView中使用排序方法，并添加了排序表达式。我正试图编写c#代码，这将允许排序，但我不确定我将如何去做，因为我不使用SQL数据源:
protected void GridView1_Sorting(object server, GridViewSortEventArgs e)
{
switch (e.SortExpression)
{
case "FileName":
if (e.SortDirection == SortDirection.Ascending)
{
GridView1.DataSource = Session["fileData"];//DO BY ASCENDING
GridView1.DataBind();
}
else
{
GridView1.DataSource = Session["fileData"];//DO BY DESCENDING
GridView1.DataBind();
}
break;
case "FileDate":
break;
}
}
更新:我是如何能够让它正确工作的…
protected void Page_Load(object sender, EventArgs e)
{
string strDirectory = @"C:'PDFGenerate'";
try
{
if (!Directory.Exists(strDirectory))
{
Directory.CreateDirectory(strDirectory);
}
}
catch (Exception ce)
{
//tc.Text = "Unable to create directory to save generated PDF files";
}
if (!Page.IsPostBack) //loaded first time...
{
//MessageBox.Show("Fires from a PAGE REFRESH or FIRST VISIT");
BindData();
}
else //loaded after an event (button click, link click, etc.)
{
//MessageBox.Show("Fires from an EVENT");
}
}
protected void BindData()
{
try
{
filePaths = Directory.GetFiles(@"C:'PDFGenerate");
files = new List<ListItem>();
foreach (string filePath in filePaths)
{
files.Add(new ListItem(Path.GetFileName(filePath), File.GetLastWriteTime(filePath).ToString()));
}
GridView1.DataSource = files;
GridView1.DataBind();
Session["fileData"] = files;
}
catch (Exception ce)
{
}
//MessageBox.Show(files.Count() + ""); // displays the count for the files being displayed
}
protected void GridView1_Sorting(object server, GridViewSortEventArgs e)
{
DataBind();
string strSortExpression = e.SortExpression;
switch (strSortExpression)
{
case "FileName":
if (e.SortExpression == (string)ViewState["SortColumn"])
{
// We are resorting the same column, so flip the sort direction
e.SortDirection =
((SortDirection)ViewState["SortColumnDirection"] == SortDirection.Ascending) ?
SortDirection.Descending : SortDirection.Ascending;
}
if (e.SortDirection == SortDirection.Ascending)
{
//MessageBox.Show("ASC");
var dataTable = ToDataTable((IList<ListItem>)Session["fileData"]);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}", "Text", e.SortDirection == SortDirection.Ascending ? "ASC" : "DESC");
GridView1.DataSource = dataView;
GridView1.DataBind();
}
else
{
//MessageBox.Show("DESC");
var dataTable = ToDataTable((IList<ListItem>)Session["fileData"]);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}", "Text", e.SortDirection == SortDirection.Descending ? "DESC" : "ASC");
GridView1.DataSource = dataView;
GridView1.DataBind();
}
ViewState["SortColumn"] = e.SortExpression;
ViewState["SortColumnDirection"] = e.SortDirection;
break;
case "FileDate":
if (e.SortExpression == (string)ViewState["SortColumn"])
{
// We are resorting the same column, so flip the sort direction
e.SortDirection =
((SortDirection)ViewState["SortColumnDirection"] == SortDirection.Ascending) ?
SortDirection.Descending : SortDirection.Ascending;
}
if (e.SortDirection == SortDirection.Ascending)
{
var dataTable = ToDataTable((IList<ListItem>)Session["fileData"]);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}", "Value", e.SortDirection == SortDirection.Ascending ? "ASC" : "DESC");
GridView1.DataSource = dataView;
GridView1.DataBind();
}
else
{
var dataTable = ToDataTable((IList<ListItem>)Session["fileData"]);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}", "Value", e.SortDirection == SortDirection.Descending ? "DESC" : "ASC");
GridView1.DataSource = dataView;
GridView1.DataBind();
}
ViewState["SortColumn"] = e.SortExpression;
ViewState["SortColumnDirection"] = e.SortDirection;
break;
}
}
public DataTable ToDataTable(IList<ListItem> data)
{
var table = new DataTable();
table.Columns.Add("Value", typeof(string));
table.Columns.Add("Text", typeof(string));
foreach (var item in data)
{
var row = table.NewRow();
row["Value"] = item.Value;
row["Text"] = item.Text;
table.Rows.Add(row);
}
return table;
}
虽然不建议在视图的代码后面放置逻辑，但您可以使用以下代码实现:
protected void GridView1_Sorting(object server, GridViewSortEventArgs e)
{
switch (e.SortExpression)
{
case "FileName":
var dataTable = ToDataTable((IList<ListItem>)Session["fileData"]);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}",
e.SortExpression,
e.SortDirection == SortDirection.Ascending
? "ASC" : "DESC");
GridView1.DataSource = dataView;
GridView1.DataBind();
case "FileDate":
break;
}
}
同时，确保集合中的项目实现System.IComparable<T>
最后，添加以下代码将会话数据加载到dataTable中:
public DataTable ToDataTable(IList<ListItem> data)
{
var table = new DataTable();
table.Columns.Add("Value", typeof(string));
table.Columns.Add("Text", typeof(string));
foreach (var item in data)
{
var row = table.NewRow();
row["Value"] = item.Value;
row["Text"] = item.Text;
table.Rows.Add(row);
}
return table;
}
要使代码按照我之前回答的讨论中所要求的加载排序，请执行以下操作:
创建一个名为sort的方法:
public void Sort(IList<ListItem> items, SortDirection direction)
{
var dataTable = ToDataTable(items);
var dataView = new DataView(dataTable);
dataView.Sort = string.Format("{0} {1}", "Text",
direction == SortDirection.Ascending ? "ASC" : "DESC");
GridView1.DataSource = dataView;
GridView1.DataBind();
}
更改BindData的实现为:
protected void BindData()
{
try
{
filePaths = Directory.GetFiles(@"C:'PDFGenerate");
files = new List<ListItem>();
foreach (string filePath in filePaths)
{
files.Add(new ListItem(Path.GetFileName(filePath), File.GetLastWriteTime(filePath).ToString()));
}
Session["fileData"] = files;
Sort(files, SortDirection.Descending);
}
catch (Exception ce)
{
}
//MessageBox.Show(files.Count() + ""); // displays the count for the files being displayed
}
然后将GridView1_Sorting修改为:
protected void GridView1_Sorting(object server, GridViewSortEventArgs e)
{
string strSortExpression = e.SortExpression;
switch (strSortExpression)
{
case "FileName":
case "FileDate":
if (e.SortExpression == (string)ViewState["SortColumn"])
{
// We are resorting the same column, so flip the sort direction
e.SortDirection =
((SortDirection)ViewState["SortColumnDirection"] == SortDirection.Ascending) ?
SortDirection.Descending : SortDirection.Ascending;
}
Sort((IList<ListItem>)Session["fileData"], e.SortDirection);
ViewState["SortColumn"] = e.SortExpression;
ViewState["SortColumnDirection"] = e.SortDirection;
break;
}
}
你必须设置GridView属性:
GridView1.AllowSorting="true"
在后面的代码中(Page_Load事件)，或在Page html中:其余的详细信息见http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.allowsorting%28v=vs.110%29.aspx