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C# 检查flowLayoutPanel在c中是否为空#_C#_Winforms_Null_Label_Flowlayoutpanel - Fatal编程技术网

C# 检查flowLayoutPanel在c中是否为空#

C# 检查flowLayoutPanel在c中是否为空#,c#,winforms,null,label,flowlayoutpanel,C#,Winforms,Null,Label,Flowlayoutpanel,我想在flowLayoutPanel为空时显示错误标签,但我不知道如何检查flowLayoutPanel是否为空。这是我当前的代码: private void flowLayoutPanel1_ControlRemoved(object sender, ControlEventArgs e) { if (flowLayoutPanel1.Controls == null) { customtoolwa

我想在flowLayoutPanel为空时显示错误标签,但我不知道如何检查flowLayoutPanel是否为空。这是我当前的代码:

private void flowLayoutPanel1_ControlRemoved(object sender, ControlEventArgs e)
        {
            if (flowLayoutPanel1.Controls == null)
            {
                customtoolwarning.Visible = true;
            }
            else
            {
                customtoolwarning.Visible = false;
            }
        }
请帮忙


谢谢

您遇到的问题是您正在检查
控件
中的
null
以确定它是否为空。
控件
属性永远不会是
null
,而是非null,为空时长度为0。比如说

if (flowLayoutPanel1.Controls.Count == 0) {
  // It's empty
}

基本上什么都没有,它做的事情完全相同——只是另一种书写方式:)
private void flowLayoutPanel1_ControlRemoved(object sender, ControlEventArgs e)
        {
            if (flowLayoutPanel1.Controls.Count > 0)
            {
                customtoolwarning.Visible = true;
            }
            else
            {
                customtoolwarning.Visible = false;
            }
        }
lblNoContacts.Visible = (flowLayoutPanel.Controls.Count == 0) ? true : false;