BaseDataList.IsBindableType(Type) Metodo

  • Riferimento

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Determina se il tipo di dati specificato può essere associato a un controllo elenco derivante dalla classe BaseDataList.

public:
 static bool IsBindableType(Type ^ type);
public static bool IsBindableType (Type type);
static member IsBindableType : Type -> bool
Public Shared Function IsBindableType (type As Type) As Boolean

Parametri

type
Type

Oggetto Type che contiene il tipo di dati su cui eseguire il test.

Restituisce

Boolean

true se il tipo di dati specificato può essere associato a un controllo elenco derivante dalla classe BaseDataList; in caso contrario, false.

Esempio

Nell'esempio di codice seguente viene illustrato come usare la IsBindableType proprietà per determinare se i valori di un determinato tipo di dati possono essere associati a un DataGrid controllo.


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">
 
      DataView CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;
      }
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // Load sample data only once when the page is first loaded.
         if (!IsPostBack) 
         {

            // Retrieve sample data.
            DataView Source = CreateDataSource();


            // Bind the data source to the DataGrid control if each column  
            // in the data source contains a data type that is compatible  
            // with the DataGrid; otherwise, display an error message. 
            if(ValidateSourceTypes(Source))
            {

               ItemsGrid.DataSource = Source;
               ItemsGrid.DataBind();

            }
            else
            {

               Message.Text = "The data source is not compatible with the DataGrid control.";

            }

         }

      }

      bool ValidateSourceTypes(DataView Source)
      {
       
         // Test the data type of each column in the data source to make 
         // sure it is compatible with the DataGrid control.

         // Initialize the success flag to true.
         bool Success = true;

         // Iterate through each column of the data source and test the 
         // data type for compatibility with the DataGrid control. 
         foreach(DataColumn column in Source.Table.Columns)
         {
            if(!BaseDataList.IsBindableType(column.DataType))
            {
               Success = false;
            }
         }

         return Success;

      }

   </script>
 
<head runat="server">
    <title>BaseDataList IsBindableType Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>BaseDataList IsBindableType Example</h3>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           GridLines="Both"
           AutoGenerateColumns="true"
           runat="server">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle> 
 
      </asp:DataGrid>

      <br /><br />

      <asp:Label id="Message" 
           runat="server"/>       

   </form>
 
</body>
</html>


<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">
 
      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(string)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 8 
        
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 
 
         ' Load sample data only once when the page is first loaded.
         If Not IsPostBack Then 
  
            ' Retrieve sample data.
            Dim Source As DataView = CreateDataSource()


            ' Bind the data source to the DataGrid control if each column in 
            ' the data source contains a data type that is compatible with the 
            ' DataGrid; Otherwise, display an error message. 
            If ValidateSourceTypes(Source) Then

               ItemsGrid.DataSource = Source
               ItemsGrid.DataBind()

            Else

               Message.Text = "The data source is not compatible with the DataGrid control."

            End If

         End If

      End Sub

      Function ValidateSourceTypes(Source As DataView) As Boolean
       
         ' Test the data type of each column in the data source to make 
         ' sure it is compatible with the DataGrid control.

         ' Initialize the success flag to True.
         Dim Success As Boolean = True

         ' Iterate through each column of the data source and test the 
         ' data type for compatibility with the DataGrid control.
         Dim column As DataColumn
           
         For Each column In Source.Table.Columns

            If Not BaseDataList.IsBindableType(column.DataType) Then
         
               Success = False
            
            End If

         Next

         Return Success

      End Function

   </script>
 
<head runat="server">
    <title>BaseDataList IsBindableType Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>BaseDataList IsBindableType Example</h3>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           GridLines="Both"
           AutoGenerateColumns="true"
           runat="server">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle> 
 
      </asp:DataGrid>

      <br /><br />

      <asp:Label id="Message" 
           runat="server"/>       

   </form>
 
</body>
</html>

Commenti

Usare il IsBindableType metodo statico per determinare se il tipo di dati specificato può essere associato a un controllo elenco che eredita dalla BaseDataList classe. I tipi di dati supportati sono System.Boolean, System.SByteSystem.Int16System.UInt32System.Int64System.Int32System.UInt64System.CharSystem.UInt16System.ByteSystem.SingleSystem.DateTimeSystem.DoubleSystem.Decimale .System.String

Si applica a

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