共用方式為

RolePrincipal.IsInRole(String) 方法

  • 參考

定義

命名空間:
System.Web.Security
組件:
System.Web.dll

取得值，指出 RolePrincipal 表示的使用者是否在指定的角色中。

public:
 virtual bool IsInRole(System::String ^ role);
public:
 override bool IsInRole(System::String ^ role);
public bool IsInRole (string role);
public override bool IsInRole (string role);
abstract member IsInRole : string -> bool
override this.IsInRole : string -> bool
override this.IsInRole : string -> bool
Public Function IsInRole (role As String) As Boolean
Public Overrides Function IsInRole (role As String) As Boolean

參數

role
String

要搜尋的角色。

傳回

Boolean

如果 RolePrincipal 表示的使用者在指定的角色中，則為 true，否則為 false。

實作

IsInRole(String)

例外狀況

ProviderException

Identity 屬性為 null。

範例

下列程式代碼範例會先檢查登入的使用者是否在系統管理員角色中，再允許用戶檢視使用者角色。

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

string[] rolesArray;
MembershipUserCollection users;

public void Page_Load()
{
  Msg.Text = "";

  if (!User.IsInRole("Administrators"))
  {
    Msg.Text = "You are not authorized to view user roles.";
    UsersListBox.Visible = false;
    return;
  }

  if (!IsPostBack)
  {
    // Bind users to ListBox.

    users = Membership.GetAllUsers();
    UsersListBox.DataSource = users;
    UsersListBox.DataBind();
  }


  // If a user is selected, show the roles for the selected user.

  if (UsersListBox.SelectedItem != null)
  {
    // Bind roles to GridView.

    rolesArray = Roles.GetRolesForUser(UsersListBox.SelectedItem.Value);
    UserRolesGrid.DataSource = rolesArray;
    UserRolesGrid.DataBind();

    UserRolesGrid.Columns[0].HeaderText = "Roles for " + UsersListBox.SelectedItem.Value;
  }
}

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Sample: View User Roles</title>
</head>
<body>

<form runat="server" id="PageForm">

  <h3>View User Roles</h3>

  <asp:Label id="Msg" ForeColor="maroon" runat="server" /><br />

  <table border="0" cellspacing="4">
    <tr>
      <td valign="top"><asp:ListBox id="UsersListBox" DataTextField="Username" 
                                    Rows="8" AutoPostBack="true" runat="server" /></td>
      <td valign="top"><asp:GridView runat="server" CellPadding="4" id="UserRolesGrid" 
                                     AutoGenerateColumns="false" Gridlines="None" 
                                     CellSpacing="0" >
                         <HeaderStyle BackColor="navy" ForeColor="white" />
                         <Columns>
                           <asp:TemplateField HeaderText="Roles" >
                             <ItemTemplate>
                               <%# Container.DataItem.ToString() %>
                             </ItemTemplate>
                           </asp:TemplateField>
                         </Columns>
                       </asp:GridView></td>
    </tr>
  </table>

</form>

</body>
</html>

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

Dim rolesArray() As String
Dim users As MembershipUserCollection

Public Sub Page_Load()

  Msg.Text = ""

  If Not User.IsInRole("Administrators") Then
    Msg.Text = "You are not authorized to view user roles."
    UsersListBox.Visible = False
    Return
  End If

  If Not IsPostBack Then
    ' Bind users to ListBox.

    users = Membership.GetAllUsers()
    UsersListBox.DataSource = users
    UsersListBox.DataBind()
  End If


  ' If a user is selected, show the roles for the selected user.

  If Not UsersListBox.SelectedItem Is Nothing Then
    ' Bind roles to GridView.

    rolesArray = Roles.GetRolesForUser(UsersListBox.SelectedItem.Value)
    UserRolesGrid.DataSource = rolesArray
    UserRolesGrid.DataBind()

    UserRolesGrid.Columns(0).HeaderText = "Roles for " & UsersListBox.SelectedItem.Value
  End If

End Sub

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Sample: View User Roles</title>
</head>
<body>

<form runat="server" id="PageForm">

  <h3>View User Roles</h3>

  <asp:Label id="Msg" ForeColor="maroon" runat="server" /><br />

  <table border="0" cellspacing="4">
    <tr>
      <td valign="top"><asp:ListBox id="UsersListBox" DataTextField="Username" 
                                    Rows="8" AutoPostBack="true" runat="server" /></td>
      <td valign="top"><asp:GridView runat="server" CellPadding="4" id="UserRolesGrid" 
                                     AutoGenerateColumns="false" Gridlines="None" 
                                     CellSpacing="0" >
                         <HeaderStyle BackColor="navy" ForeColor="white" />
                         <Columns>
                           <asp:TemplateField HeaderText="Roles" >
                             <ItemTemplate>
                               <%# Container.DataItem.ToString() %>
                             </ItemTemplate>
                           </asp:TemplateField>
                         </Columns>
                       </asp:GridView></td>
    </tr>
  </table>

</form>

</body>
</html>

備註

IsInRole 會先檢查 IsRoleListCached 屬性，以判斷目前使用者的角色名稱快取清單是否可用。 IsRoleListCached如果 屬性為 true，則會檢查所指定角色的快取清單。 IsInRole如果方法在快取清單中尋找指定的角色，則會傳true回 。

如果 IsInRole 找不到指定的角色，它會呼叫 GetRolesForUser 預設 Provider 實例的 方法，以判斷用戶名稱是否與所設定 ApplicationName 值的數據源中的角色相關聯。

適用於

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