我是新手,我正在创建一个简单的应用程序,我单击一个按钮,应显示桌面上的通知.我正在这样做windows form c#
错误是" NullReferenceException was unhandled
我Notify
在form1中有一个按钮.我试过这个:
Form1.cs的
public Form1()
{
InitializeComponent();
this.Load += new EventHandler(Form1_Load);
webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
webBrowser1.ScriptErrorsSuppressed = true;
}
private void btnNotify_Click(object sender, EventArgs e)
{
webBrowser1.Document.InvokeScript("notifyMe");
}
private void Form1_Load(object sender, EventArgs e)
{
string CurrentDirectory = Directory.GetCurrentDirectory();
webBrowser1.Navigate(Path.Combine(CurrentDirectory,"HTMLPage1.html"));
}
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
webBrowser1.ObjectForScripting = this;
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HTMLPage1.html的代码:
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title></title>
<script language="javascript" type="text/javascript">
document.addEventListener('DOMContentLoaded', function () {
if (Notification.permission !== "granted") …
Run Code Online (Sandbox Code Playgroud) 我的申请中有两种表格。frmLogin
和frmDash
。登录后。我hiding
frmLogin
点击登录按钮。广告显示frmDash
。
在frmDash
,有LogOut
按钮。单击注销,我正在使用this.Close()
并显示登录表单。但现在如果我点击整个应用程序的(red X)
按钮frmLogin
不会终止。lz给点建议吧。我试过这个。:
private void btnLogin_Click(object sender, EventArgs e)
{
try
{
this.Hide();
string Log_API = "http://api.retailbutton.co/WS/Service.php?Service=employeeLogin";
if (LoginUser(Log_API))
{
logIn_Status = "true";
GlolbalUtil.LogIn_Status = logIn_Status;
frmDash frmDash = new frmDash();
frmDash.Owner = this;
frmDash.Show();
txtUsername.Text = "";
txtPassword.Text = "";
//GlolbalUtil.accept_status = "1";
}
else
{
MessageBox.Show("Please Check Username and password");
FrmLogin frmLogin = new FrmLogin();
frmLogin.Owner = this;
frmLogin.Show(); …
Run Code Online (Sandbox Code Playgroud) 我有一个LinkButton
在masterpage
和的LinkButton的点击,我重定向到,比方说,Page1.aspx
.在Page1.aspx上,我有一个button1
.点击它button1
,我打开新窗口,不影响数据Page1.aspx
.
但是,当我点击LinkButton
主页,重定向到Page1.aspx
代码后面,单击时button1
,Page1.aspx
数据会被更改.
如何防止这种情况.我提供我的代码.
主页上的LinkButton:
<asp:LinkButton ID="lnkAppointMent" runat="server" OnClick="lnkAppointMent_Click"><span>Appointment Scheduler </span></asp:LinkButton>
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单击LinkButton的事件:
protected void lnkAppointMent_Click(object sender, EventArgs e)
{
Session["PhoneCenter"] = "Appointment";
Response.Redirect("PhoneMessage.aspx");
}
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PageLoad重定向页面(PhoneMessage.aspx):
protected void Page_Load(object sender, EventArgs e)
{
fillCustomTypeMessages();
if (!Page.IsPostBack)
{
.
.
.
else if (Session["PhoneCenter"].ToString() == "Appointment")
{
btnScheduleAppointments_Click(btnScheduleAppointments, null);
}
.
.
.
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PhoneMessage.aspx上的按钮:
<div style="float: right; padding-right: 120px">
<asp:Button ID="btnScheduleAppointments" runat="server" OnClick="btnScheduleAppointments_Click" …
Run Code Online (Sandbox Code Playgroud) 我在 .Net 4.5 中升级了我的旧应用程序。有一些过时的方法警告我非常想解决它们。过时的方法之一是 XmlValidatingReader。在互联网上查了一下,发现XmlReaderSettings是 XmlValidatingReader 的潜在替代品。
// ==old code==
Hashtable _SchemasCache = new Hashtable();
XmlReader xmlReader = new XmlTextReader(xmlStream);
XmlValidatingReader validatingReader = new XmlValidatingReader(xmlReader);
validatingReader.Schemas.Add(root.Namespace, schemaLocation); // both parametres are string. No error
_SchemasCache.Add(schemaLocation, validatingReader.Schemas);
// ==new code==
var schemaLocation = "res://somepath/Messages.xsd";
XmlReaderSettings settings = new XmlReaderSettings();
settings.Schemas.Add(root.Namespace, schemaLocation); // this line gives error
_SchemasCache.Add(schemaLocation, settings.Schemas);
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旧代码没有给出任何错误,但新代码给出了一个错误,The URI prefix is not recognized.
我找不到 的这种行为的原因settings.Schemas.Add()
,因为它与XmlValidatingReader
. 有人能帮忙吗?
编辑:这里schemaLocation 的值是“res://somepath/Messages.xsd”。因为 schemaLocation没有Http: …
我正在从Technology
下拉列表中的表中检索数据ddlTechnology
.
我TechnologyId
在表中有主键,值为1,2,3,4
现在根据技术,我必须在问题库中添加问题.但是当我选择下拉列表中的任何项目时,我SelectedIndex
的总是0.
我想TechnologyId
从下拉列表.
我试过以下代码,但它不起作用
using (dbDataContext dt = new dbDataContext())
{
var qry = from i in dt.Technologies
select i;
ddlTechnology.DataSource = qry;
ddlTechnology.DataValueField = "TechnologyId";
ddlTechnology.DataTextField = "TechnologyName";
ddlTechnology.DataBind();
ddlTechnology.Items.Insert(0, new ListItem("Select Technology", ""));
}
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添加按钮以根据所选技术添加问题.
protected void btnAdd_Click(object sender, EventArgs e)
{
using (dbDataContext dt = new dbDataContext())
{
Question objQtn = new Question();
objQtn.Question1 = txtQuestion.Text;
objQtn.Option1 = txtOption1.Text;
objQtn.Option2 = txtOption2.Text;
objQtn.Option3 = txtOption3.Text;
objQtn.Answer …
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