Alert
in namespace DotVVM.BusinessPack.Controls
Renders a contextual feedback message for users.
Usage & Scenarios
Renders an alert message of a specified type. It can be used to indicate errors, warnings, info or success messages.
The user can dismiss it by clicking an icon. The alert can be also hidden after a specified timeout.
Sample 1: Alert Types
The Type
of the alert can be Success
, Info
, Warning
and Danger
. An icon symbolizing the alert type is displayed on the left side by default. You can set the ShowDefaultIcon
property to false
if you want to hide the default icons.
Use the Text
property to specify the text. Alternatively, you can place any content inside the Alert
control.
<bp:Alert Type="Success" Text="Plain text success alert" />
<bp:Alert Type="Danger" ShowDefaultIcon="false">
Danger alert with <a href="#">hyperlinks</a>
<br />
and custom content
</bp:Alert>
Sample 2: Dismiss
The AllowDismiss
property will add an icon to the right side of the alert, allowing the user to hide the alert. The Dismissed
command is triggered when the alert is hidden by user.
The DismissIcon
can be used to specify custom dismiss icon.
You can also use the AutoHideTimeout
property to hide the alert automatically after being displayed for specified number of seconds. The Dismissed
command is not triggered in this case.
<bp:Alert Type="Warning"
AllowDismiss="true"
Dismissed="{command: Dismissed()}"
Text="This alert can be dismissed." />
<bp:Alert Type="Danger"
AllowDismiss="true"
Text="This alert can be dismissed and uses a custom dismiss icon.">
<DismissIcon>
<bp:Icon Icon="Trash" />
</DismissIcon>
</bp:Alert>
<bp:Alert Type="Info"
AutoHideTimeout="5"
Text="This alert will hide automatically." />
using DotVVM.Framework.ViewModel;
namespace DotvvmWeb.Views.Docs.Controls.businesspack.Alert.sample2
{
public class ViewModel : DotvvmViewModelBase
{
public void Dismissed()
{
// handle the dismissed command
}
}
}
Sample 3: Display State
You can use the IsDisplayed
property to determine or specify, whether the alert is displayed.
If you set this property to true
, the alert will be displayed. When the alert is hidden, the property will be switched to false
.
If the IsDisplayed
property is not set, the alert is displayed whenever the Text
is not null
or empty.
<bp:Alert Type="Warning"
IsDisplayed="{value: IsDisplayed}"
AllowDismiss="true"
Text="Warning" />
<bp:Alert Type="Danger"
AllowDismiss="true"
Text="{value: ErrorMessage}" />
<bp:CheckBox Text="Is warning displayed"
Checked="{value: IsDisplayed}" />
using DotVVM.Framework.ViewModel;
namespace DotvvmWeb.Views.Docs.Controls.businesspack.Alert.sample3
{
public class ViewModel : DotvvmViewModelBase
{
public bool IsDisplayed { get; set; }
public string ErrorMessage { get; set; }
}
}
Sample 4: Common Usage
The typical use of the Alert
control is to have 2 properties in the viewmodel (AlertText
and AlertType
) which are bound to the properties of the Alert
control.
Notice that the properties are marked with the Bind
attribute setting the direction to ServerToClient
. That's because we don't need to send the property values to the server when we are making a postback. We only need to send the new value to the client if the properties are changed.
We suggest to put the AlertText
and AlertType
properties into the base viewmodel class and create a method which does this kind of exception handling. Then you can use it on all places in your application.
<bp:Alert Text="{value: AlertText}" Type="{value: AlertType}" />
<bp:Button Text="Do Something" Click="{command: DoSomething()}" />
namespace DotvvmWeb.Views.Docs.Controls.businesspack.Alert.sample4
{
public class ViewModel : MyViewModelBase
{
public void DoSomething()
{
ExecuteWithAlert(() =>
{
// the action
});
}
}
}
using System;
using DotVVM.Framework.ViewModel;
using DotVVM.Framework.Hosting;
using DotVVM.BusinessPack.Controls;
namespace DotvvmWeb.Views.Docs.Controls.businesspack.Alert.sample4
{
public class MyViewModelBase : DotvvmViewModelBase
{
[Bind(Direction.ServerToClient)]
public string AlertText { get; set; }
[Bind(Direction.ServerToClient)]
public AlertType AlertType { get; set; }
/// <summary>
/// Executes the specified action and sets the appropriate alert messages.
/// </summary>
protected void ExecuteWithAlert(Action actionToExecute,
string successText = "The operation was successful.",
string errorText = "Sorry, an unexpected error has occurred.")
{
try
{
actionToExecute();
AlertText = successText;
AlertType = AlertType.Success;
}
catch (Exception ex) when (!(ex is DotvvmInterruptRequestExecutionException))
{
AlertText = errorText;
AlertType = AlertType.Danger;
}
}
}
}
Properties
Name | Type | Description | Notes | Default Value | |
---|---|---|---|---|---|
AllowDismiss | Boolean | Gets or sets whether a close icon should be displayed in the Alert box. |
attribute
static value
bindable
|
False | |
AutoHideTimeout | Double | Gets or sets after how many seconds is the Alert message automatically hidden. If the value is equal to 0, Alert is not auto-hidden. The default value is 0 seconds. |
attribute
static value
bindable
|
0 | |
ClientIDMode | ClientIDMode | Gets or sets the client ID generation algorithm. |
attribute
static value
|
Static | |
ContentTemplate | ITemplate | Gets or sets a template rendering contents of the control. |
inner element
static value
bindable
default
|
null | |
DataContext | Object | Gets or sets a data context for the control and its children. All value and command bindings are evaluated in context of this value. The DataContext is null in client-side templates. |
attribute
bindable
|
null | |
DisableContentStyle | Boolean |
attribute
static value
bindable
|
False | ||
DismissIcon | IconBase | Gets or sets the close icon displayed when the Alert is dismissible. |
inner element
static value
bindable
|
null | |
ID | String | Gets or sets the control client ID within its naming container. |
attribute
static value
bindable
|
null | |
IncludeInPage | Boolean | Gets or sets whether the control is included in the DOM of the page. |
attribute
bindable
|
True | |
IsDisplayed | Boolean | Gets or sets the value indicating whether the Alert is actually visible. The value is ignored when Visible property is set to false. |
attribute
bindable
|
True | |
ShowDefaultIcon | Boolean | Gets or sets the value indicating whether the type icon is displayed. It's displayed by default. |
attribute
static value
bindable
|
True | |
Text | String | Gets or sets the text displayed inside the Alert box. |
attribute
static value
bindable
|
null | |
Type | AlertType | Gets or sets the type (color, severity) of the Alert message. |
attribute
static value
bindable
|
Success | |
Visible | Boolean |
attribute
bindable
|
True |
Events
Name | Type | Description | |
---|---|---|---|
Dismissed | Command | Gets or sets the command triggered when the Alert message is dismissed by user. |