如何：在 Calendar 控件中显示数据库中的选定日期

Calendar 控件并不直接支持数据绑定，也就是说，您不是将日历作为一个整体绑定到数据源。相反，您编写代码来获取所需数据，然后就可以在 DayRender 事件中，将当前呈现的日期与从数据源读取的数据进行比较。

在 Calendar 控件中显示数据库数据

使用 ADO.NET 类型连接到数据库并查询要显示的日期。

在 Calendar 控件的 DayRender 事件中，将当前呈现的日期与从数据库中检索到的数据进行比较。如果存在匹配项，则自定义相应的日期显示。

示例

下面的示例将假日信息从数据库读取到一个 ADO.NET 数据集。当您选定一个月份时，将获取当前所选月份的日期，此日期范围是基于 Calendar 控件的 VisibleDate 属性定义的，该属性返回当前月的第一个日期。每次用户导航到一个新的月份时，代码就会读取该月份的假日。在 DayRender 事件中，代码会将当前呈现的日期与从数据库返回的日期进行比较。如果有匹配的日期，则用特殊颜色标记这一天。

Visual Basic


复制代码

Protected dsHolidays As DataSet

Protected Sub Page_Load(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
Calendar1.VisibleDate = DateTime.Today
FillHolidayDataset()
End If
End Sub

Protected Sub FillHolidayDataset()
Dim firstDate As New DateTime(Calendar1.VisibleDate.Year, _
Calendar1.VisibleDate.Month, 1)
Dim lastDate As DateTime = GetFirstDayOfNextMonth()
dsHolidays = GetCurrentMonthData(firstDate, lastDate)
End Sub

Protected Function GetFirstDayOfNextMonth() As DateTime
Dim monthNumber, yearNumber As Integer
If Calendar1.VisibleDate.Month = 12 Then
monthNumber = 1
yearNumber = Calendar1.VisibleDate.Year + 1
Else
monthNumber = Calendar1.VisibleDate.Month + 1
yearNumber = Calendar1.VisibleDate.Year
End If
Dim lastDate As New DateTime(yearNumber, monthNumber, 1)
Return lastDate
End Function

Protected Sub Calendar1_VisibleMonthChanged(ByVal sender As Object, _
ByVal e As System.Web.UI.WebControls.MonthChangedEventArgs) _
Handles Calendar1.VisibleMonthChanged
FillHolidayDataset()
End Sub

Function GetCurrentMonthData(ByVal firstDate As DateTime, _        ByVal lastDate As DateTime) As DataSet
Dim dsMonth As New DataSet
Dim cs As ConnectionStringSettings
cs = ConfigurationManager.ConnectionStrings("ConnectionString1")
Dim connString As String = cs.ConnectionString
Dim dbConnection As New SqlConnection(connString)
Dim query As String
query = "SELECT HolidayDate FROM Holidays " & _
" WHERE HolidayDate >= @firstDate AND HolidayDate < @lastDate"
Dim dbCommand As New SqlCommand(query, dbConnection)
dbCommand.Parameters.Add(New SqlParameter("@firstDate", firstDate))
dbCommand.Parameters.Add(New SqlParameter("@lastDate", lastDate))

Dim sqlDataAdapter As New SqlDataAdapter(dbCommand)
Try
sqlDataAdapter.Fill(dsMonth)
Catch
End Try
Return dsMonth
End Function

Protected Sub Calendar1_DayRender(ByVal sender As Object, _
ByVal e As System.Web.UI.WebControls.DayRenderEventArgs) _
Handles Calendar1.DayRender
Dim nextDate As DateTime
If Not dsHolidays Is Nothing Then
For Each dr As DataRow In dsHolidays.Tables(0).Rows
nextDate = CType(dr("HolidayDate"), DateTime)
If nextDate = e.Day.Date Then
e.Cell.BackColor = System.Drawing.Color.Pink
End If
Next
End If
End Sub

C#


复制代码

protected DataSet dsHolidays;

protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
Calendar1.VisibleDate = DateTime.Today;
FillHolidayDataset();
}
}

protected void FillHolidayDataset()
{
DateTime firstDate = new DateTime(Calendar1.VisibleDate.Year,
Calendar1.VisibleDate.Month, 1);
DateTime lastDate = GetFirstDayOfNextMonth();
dsHolidays = GetCurrentMonthData(firstDate, lastDate);
}

protected DateTime GetFirstDayOfNextMonth()
{
int monthNumber, yearNumber;
if(Calendar1.VisibleDate.Month == 12)
{
monthNumber = 1;
yearNumber = Calendar1.VisibleDate.Year + 1;
}
else
{
monthNumber = Calendar1.VisibleDate.Month + 1;
yearNumber = Calendar1.VisibleDate.Year;
}
DateTime lastDate = new DateTime(yearNumber, monthNumber, 1);
return lastDate;
}

protected DataSet GetCurrentMonthData(DateTime firstDate,
DateTime lastDate)
{
DataSet dsMonth = new DataSet();
ConnectionStringSettings cs;
cs = ConfigurationManager.ConnectionStrings["ConnectionString1"];
String connString = cs.ConnectionString;
SqlConnection dbConnection = new SqlConnection(connString);
String query;
query = "SELECT HolidayDate FROM Holidays " + _
" WHERE HolidayDate >= @firstDate AND HolidayDate < @lastDate";
SqlCommand dbCommand = new SqlCommand(query, dbConnection);
dbCommand.Parameters.Add(new SqlParameter("@firstDate",
firstDate));
dbCommand.Parameters.Add(new SqlParameter("@lastDate", lastDate));

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(dbCommand);
try
{
sqlDataAdapter.Fill(dsMonth);
}
catch {}
return dsMonth;
}

protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
{
DateTime nextDate;
if(dsHolidays != null)
{
foreach(DataRow dr in dsHolidays.Tables[0].Rows)
{
nextDate = (DateTime) dr["HolidayDate"];
if(nextDate == e.Day.Date)
{
e.Cell.BackColor = System.Drawing.Color.Pink;
}
}
}
}
protected void Calendar1_VisibleMonthChanged(object sender,
MonthChangedEventArgs e)
{
FillHolidayDataset();
}

此示例基于当前显示的月份的日期生成一个查询。VisibleDate 属性返回当前月的第一个日期。（在用户导航到日历中之前，不会设置 VisibleDate 属性，因此在第一次显示该页时，代码会手动设置 VisibleDate 属性。）代码中的一个辅助函数会根据 VisibleDate 属性计算下个月的第一天，因此可以用于生成当前月的日期范围。

编译代码

代码假设使用的是一个 SQL Server 数据库，其中包含 Holidays 表。该表具有列 HolidayDate。连接到该数据库所需的连接字符串存储在 Web.config 文件中，名为 ConnectionString1。

代码假设已经导入了命名空间 System.Data 和 System.Data.SqlClient，因此无需完全限定即可使用对 DataSet、SqlConnection 和其他对象的引用。

可靠编程

查询数据库时，应始终将查询的执行（在此示例中，即为调用数据适配器的 Fill 方法时）包含在一个 try-catch 块中。

请参见

概念

Calendar Web 服务器控件概述