textbox.Focus() 在 C# 中不起作用 [英] textbox.Focus() not working in C#

问题描述

我想知道为什么这段代码无法聚焦文本框...?

private void sendEmail_btn_Click(object sender, EventArgs e){字符串 sendTo = recipientEmail_tbx.Text.Trim();if (!IsValidEmailAddress(sendTo)){MessageBox.Show("请输入有效的电子邮件地址","Cognex" MessageBoxButtons.OK, MessageBoxIcon.Error);收件人电子邮件_tbx.Focus();}}

解决方案

使用 Select() 代替:

recipientEmail_tbx.Select();

<块引用>

Focus 是一种低级方法，主要用于自定义控件作者.相反，应用程序程序员应该对子控件使用 Select 方法或 ActiveControl 属性，或对表单使用 Activate 方法.

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.focus.aspx

am wondering why this code fails to focus the textbox...?

private void sendEmail_btn_Click(object sender, EventArgs e)
{    
    String sendTo = recipientEmail_tbx.Text.Trim();
    if (!IsValidEmailAddress(sendTo))
    {
        MessageBox.Show("Please Enter valid Email address","Cognex" MessageBoxButtons.OK, MessageBoxIcon.Error);                
        recipientEmail_tbx.Focus();
    }
}

解决方案

Use Select() instead:

recipientEmail_tbx.Select();

Focus is a low-level method intended primarily for custom control authors. Instead, application programmers should use the Select method or the ActiveControl property for child controls, or the Activate method for forms.

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.focus.aspx

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