如果打开关闭表格，如何检查表格是否打开？

如何检查表单是否已打开，以及表单是否打开以关闭表单？

我尝试了下面的代码，测试了一些代码，但它仍然说即使我知道这个代码是不正常的：

foreach(Form a in Application.OpenForms) { if (a is YouLikeHits_Settings) { // About form is open MessageBox.Show("form open"); break; } // About form is not open... MessageBox.Show("form not open"); break; } 

Answer 1

Application.OpenForms包含打开的表单。 如果此集合中有表单，则会打开它。 否则它没有打开（可能关闭）。

 if (Application.OpenForms.OfType().Any()) MessageBox.Show("Form is opened"); else MessageBox.Show("Form is not opened"); 

Answer 2

这将确定

  if (Application.OpenForms.OfType().Any()) { Application.OpenForms.OfType().First().Close(); } frm_YouLikeHits_Settings f1= new frm_YouLikeHits_Settings(); f1.MdiParent = this; f1.Show(); 

Answer 3

 try { if (Application.OpenForms.OfType().Any()) { talkForm frm = new talkForm(); frm.Close(); MessageBox.Show("Form is opened"); } else { talkForm frm = new talkForm(); frm.Show(); MessageBox.Show("Form is not opened"); } } catch(Exception ex) { }