如何在TextChange上将Textbox.Enabled从false设置为true？ [英] How to set Textbox.Enabled from false to true on TextChange?

问题描述

我通过两个文本框以编程方式创建一个表单。我的目标是禁用一个文本框，如果我在第二个中输入一些东西，并且相反。我设法在第一个 textbox textchange上禁用第二个文本框，但是无法弄清楚如何在第一个 textbox .Text为空。

I programmatically create a Form with two textboxes. My goal is to disable one textbox if I type something in the second one and contrariwise. I managed to disable second textbox on first textbox textchange,but can't figure out how enable it when the first textbox.Text is empty.

以下是代码：

private void metaName_TextChanged(object sender,EventArgs e)
    {
        var ctrl = (Control)sender;
        var frm = ctrl.FindForm();

        TextBox metaTxt = null;
        foreach (var ctr in frm.Controls)
        {
            if (ctr is TextBox)
            {
                metaTxt = (TextBox)ctr;
                if (metaTxt.Name == "metaHTTPEquiv")
                {
                    metaTxt.Enabled = false;
                }
                else
                    if (?)
                    {

                    }
            }
        }
    }

我想要这样做：

if(textBox3.Text == String.Empty)
        {
            textBox4.Enabled = true;
        }
        else
            if(textBox3.Text != String.Empty)
        {
            textBox4.Enabled = false;
        }

推荐答案

首先设置一个标志来启用或者基于引发事件的metaName文本框的内容禁用第二个控件，然后使用一点Linq搜索第二个文本框。

First set a flag to enable or disable the second control based on the content of the metaName textbox that raises the event, then search for the second textbox using a bit of Linq.

private void metaName_TextChanged(object sender,EventArgs e)
{
    TextBox ctrl = sender as TextBox;
    if(ctrl != null)
    {
         bool enable = !string.IsNullOrEmpty(ctrl.Text);
         TextBox secondOne = this.Controls
                       .OfType<TextBox>()
                       .FirstOrDefault(x => x.Name == "metaHTTPEquiv");
        if(secondOne != null)
           secondOne.Enabled = enable;
    }
}

相同的代码，反转文本框角色可以是用作第二个文本框的事件处理程序。

The same code, reversing the textboxes roles, could be used as the event handler of the second textbox.

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