1

我想创建一个自定义客户端 (OnClientClick) 事件，我可以在 asp.net 页面的标记中订阅该事件，就像框架中包含的普通 asp.net 控件一样。有谁知道任何好的例子或教程来展示如何使用用户控件来做到这一点？

假设我的用户控件名为 AwsomeUserControl.ascx

 <asp:AwsomeUserControl OnclientClick='javascript:
   alert('Hello I am a client side alert from a custom control')'/>
4

3 回答 3

2

它基本上是将给定的字符串值呈现给客户端。

public partial class AwsomeUserControl : System.Web.UI.UserControl
{
    public string OnClientClick { get; set; }

    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Page_PreRender(object sender, EventArgs e)
    {
        if (!string.IsNullOrWhiteSpace(OnClientClick))
        {
            ScriptManager.RegisterStartupScript(this, GetType(), "script", 
            OnClientClick, true);
        }
    }
}

然而，实际的 ASP.Net Button 控件的 OnClientClick 事件远不止这些。您可以使用 Reshaper 或一些反编译工具查看它们。

这是源代码 -

/// Adds the attributes of the <see cref="T:System.Web.UI.WebControls.Button"/> control to the output stream for rendering on the client.
/// </summary>
/// <param name="writer">An <see cref="T:System.Web.UI.HtmlTextWriter"/> that contains the output stream to render on the client. </param>
protected override void AddAttributesToRender(HtmlTextWriter writer)
{
    bool useSubmitBehavior = this.UseSubmitBehavior;
    if (this.Page != null)
        this.Page.VerifyRenderingInServerForm((Control)this);
    if (useSubmitBehavior)
        writer.AddAttribute(HtmlTextWriterAttribute.Type, "submit");
    else
        writer.AddAttribute(HtmlTextWriterAttribute.Type, "button");
    PostBackOptions postBackOptions = this.GetPostBackOptions();
    string uniqueId = this.UniqueID;
    if (uniqueId != null && (postBackOptions == null || postBackOptions.TargetControl == this))
        writer.AddAttribute(HtmlTextWriterAttribute.Name, uniqueId);
    writer.AddAttribute(HtmlTextWriterAttribute.Value, this.Text);
    bool isEnabled = this.IsEnabled;
    string firstScript = string.Empty;
    if (isEnabled)
    {
        firstScript = Util.EnsureEndWithSemiColon(this.OnClientClick);
        if (this.HasAttributes)
        {
            string str = this.Attributes["onclick"];
            if (str != null)
            {
                firstScript = firstScript + Util.EnsureEndWithSemiColon(str);
                this.Attributes.Remove("onclick");
            }
        }
        if (this.Page != null)
        {
            string backEventReference = this.Page.ClientScript.GetPostBackEventReference(postBackOptions, false);
            if (backEventReference != null)
                firstScript = Util.MergeScript(firstScript, backEventReference);
        }
    }
    if (this.Page != null)
        this.Page.ClientScript.RegisterForEventValidation(postBackOptions);
    if (firstScript.Length > 0)
    {
        writer.AddAttribute(HtmlTextWriterAttribute.Onclick, firstScript);
        if (this.EnableLegacyRendering)
            writer.AddAttribute("language", "javascript", false);
    }
    if (this.Enabled && !isEnabled && this.SupportsDisabledAttribute)
        writer.AddAttribute(HtmlTextWriterAttribute.Disabled, "disabled");
    base.AddAttributesToRender(writer);
}
于 2013-11-12T21:49:13.117 回答
1

你可以这样写：

protected void print_click(object sender,eventargs e)
{
  //when i click this button i need to call javascript function
    System.Text.StringBuilder sb = new System.Text.StringBuilder();
            sb.Append(@"<script language="'javascript'">");
            sb.Append(@"example();");
            sb.Append(@"</script>");
     System.Web.UI.ScriptManager.RegisterStartupScript(this, this.GetType(), "JCall1", sb.ToString(), false);
}

可以使用 JavaScript 执行：ScriptManager.RegisterStartupScript
此链接可能很有用： 示例：如何在 C# 中执行 javascript

于 2013-11-12T21:54:55.323 回答
0

为您的用户控件提供一个客户端 ID 并使用它，例如：

<asp:AwsomeUserControl ClientID="myUserControl" />

使用 jQuery，您可以轻松地处理其上的单击事件：

$('#myUserControl').on('click', function(){
    alert('hello from my user control click!');
});
于 2013-11-12T21:48:53.803 回答