ASP.NET TextBox LostFocus 事件

问题描述

当文本框失去焦点时，我需要在服务器端触发代码.

I need to trigger code on the server side to be called when a TextBox loses focus.

我知道有 onblur 客户端事件，并且没有 LostFocus 事件，那么当我的 TextBox 失去焦点时如何导致回发?

I know there is the onblur client side event, and that there is no LostFocus event, so how can I cause a postback to occur when my TextBox loses focus?

更新:

我找到了一个 blog 似乎为此提供了一个相当不错的解决方案.它涉及向 TextBox 子类添加自定义事件，并在 onblur JavaScript 客户端事件中注册调用服务器端事件的客户端脚本.

I have found a blog which seems to give a pretty decent solution to this. It involves adding a custom event to a TextBox subclass, and registering a client script which calls the server-side event in the onblur JavaScript client event.

以下是我在VB中的实现:

The following is my implementation in VB:

Public Class MyTextBox
    Inherits TextBox
    Implements IPostBackEventHandler

    Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
        MyBase.OnInit(e)
        If Not Page.ClientScript.IsClientScriptBlockRegistered("OnBlurTextBoxEvent") Then
            Page.ClientScript.RegisterStartupScript(MyBase.GetType, "OnBlurTextBoxEvent", GetScript, True)
            Attributes.Add("onblur", "OnBlurred('" & UniqueID & "','')")
        End If
    End Sub

    Public Delegate Sub OnBlurDelegate(ByVal sender As Object, ByVal e As EventArgs)

    Public Event Blur As OnBlurDelegate

    Protected Sub OnBlur()
        RaiseEvent Blur(Me, EventArgs.Empty)
    End Sub

    Private Function GetScript() As String
        Return "function OnBlurred(control, arg)" & vbCrLf & _
                "{" & vbCrLf & _
                "    __doPostBack(control, arg);" & vbCrLf & _
                "}"
    End Function

    Public Sub RaisePostBackEvent(ByVal eventArgument As String) Implements System.Web.UI.IPostBackEventHandler.RaisePostBackEvent
        OnBlur()
    End Sub
End Class

推荐答案

我找到了一个blog 似乎为此提供了一个相当不错的解决方案.它涉及向 TextBox 子类添加自定义事件，并在 onblur JavaScript 客户端事件中注册调用服务器端事件的客户端脚本.

I have found a blog which seems to give a pretty decent solution to this. It involves adding a custom event to a TextBox subclass, and registering a client script which calls the server-side event in the onblur JavaScript client event.

以下是我在VB中的实现:

The following is my implementation in VB:

Public Class MyTextBox
    Inherits TextBox
    Implements IPostBackEventHandler

    Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
        MyBase.OnInit(e)
        If Not Page.ClientScript.IsClientScriptBlockRegistered("OnBlurTextBoxEvent") Then
            Page.ClientScript.RegisterStartupScript(MyBase.GetType, "OnBlurTextBoxEvent", GetScript, True)
            Attributes.Add("onblur", "OnBlurred('" & UniqueID & "','')")
        End If
    End Sub

    Public Delegate Sub OnBlurDelegate(ByVal sender As Object, ByVal e As EventArgs)

    Public Event Blur As OnBlurDelegate

    Protected Sub OnBlur()
        RaiseEvent Blur(Me, EventArgs.Empty)
    End Sub

    Private Function GetScript() As String
        Return "function OnBlurred(control, arg)" & vbCrLf & _
                "{" & vbCrLf & _
                "    __doPostBack(control, arg);" & vbCrLf & _
                "}"
    End Function

    Public Sub RaisePostBackEvent(ByVal eventArgument As String) Implements System.Web.UI.IPostBackEventHandler.RaisePostBackEvent
        OnBlur()
    End Sub
End Class

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