我一直在研究这个非常简单的程序，该程序使用组合框和列表来显示“书籍”，允许打印和预览，并且作业告诉我创建表单“关于表单” ，这是在单击“关于”选项卡时加载的表单。但是每次我点击它，VS都会创建一个新类，我得到了这个
“未执行例外”
错误，虽然程序没有任何错误。不确定为什么Visual Studio尝试为“about form”创建一个新的类/代码，即使我已经创建了它。我认为通过VS生成东西会有所帮助，但程序仍然不能正常工作。
这是我的关于表单代码：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace CS10AboutForm.cs
{
public partial class frmAbout : Form
{
public frmAbout()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
我尝试加载表单时遇到的错误和由VS 创建的类：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CS10.cs
{
class frmAbout
{
internal void ShowDialog()
{
throw new NotImplementedException();
}
}
}
我使用“约”形式的其他表单的代码：
namespace CS10.cs
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void lblEdit_Click(object sender, EventArgs e)
{
}
private void menuStrip2_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
}
private void addBookToolStripMenuItem_Click(object sender, EventArgs e)
{
// Add a new book to the list
if (cboBooks.Text != "")
{
cboBooks.Items.Add(cboBooks.Text);
cboBooks.Text = "";
}
else
{
MessageBox.Show("Enter a book to add", "Missing data",
MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
cboBooks.Focus();
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void editToolStripMenuItem_Click(object sender, EventArgs e)
{
}
private void mnuEditRemove_Click(object sender, EventArgs e)
{
// Remove the selected book from the list
if (cboBooks.SelectedIndex != -1)
{
cboBooks.Items.RemoveAt(cboBooks.SelectedIndex);
}
else
{
MessageBox.Show("First select a book to remove",
"No selection made", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
private void mnuEditClear_Click(object sender, EventArgs e)
{
// Clear the book list
DialogResult responseDialogResult;
responseDialogResult = MessageBox.Show("Clear the book list?",
"Clear book list", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (responseDialogResult == DialogResult.Yes)
{
cboBooks.Items.Clear();
}
}
private void mnuEditCount_Click(object sender, EventArgs e)
{
// Display a count of the books on the list
MessageBox.Show("The number of book types is " + cboBooks.Items.Count.ToString());
}
private void mnuHelpAbout_Click(object sender, EventArgs e)
{
// Create an instance and display frmAbout
frmAbout frmAboutObj = new frmAbout();
frmAboutObj.ShowDialog(); //.ShowDialog displays as a Model Form
}
private void mnuFileExit_Click(object sender, EventArgs e)
{
this.Close();
}
private void mnuFilePrintPreview_Click(object sender, EventArgs e)
{
// Begin print preview by assigning PrintDocument
printPreviewDialog1.Document = printDocument1;
printPreviewDialog1.ShowDialog();
}
private void mnuFilePrint_Click(object sender, EventArgs e)
{
// Print by calling the Print method
printDocument1.Print();
}
private void printDocument1_PrintPage(object sender,
System.Drawing.Printing.PrintPageEventArgs e)
{
// Handle printing and print previews
// printPreviewDialog1.ShowDialog() and printDocument1.Print() trigger
// PrintPage event.
Font printFont = new Font("Arial", 12);
Font headingFont = new Font("Arial", 14, FontStyle.Bold);
float fltLineHeight = printFont.GetHeight();
float fltPrintX = e.MarginBounds.Left;
float fltPrintY = e.MarginBounds.Top;
string strPrintLine;
// Print Headings
strPrintLine = "Book List ";
e.Graphics.DrawString(strPrintLine, headingFont,
Brushes.Black, fltPrintX, fltPrintY);
strPrintLine = "By Lina";
fltPrintY += fltLineHeight;
e.Graphics.DrawString(strPrintLine, headingFont,
Brushes.Black, fltPrintX, fltPrintY);
// Leave a blank line between heading and detail line
fltPrintY += fltLineHeight * 2;
// Loop through the entire list
for (int intIndex = 0; intIndex <= cboBooks.Items.Count - 1; intIndex++)
{
// Set up a line
strPrintLine = cboBooks.Items[intIndex].ToString();
// Send the line to the graphics page object
e.Graphics.DrawString(strPrintLine, printFont,
Brushes.Black, fltPrintX, fltPrintY);
// Increment the Y position for the next line
fltPrintY += fltLineHeight;
}
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void printPreviewDialog1_Load(object sender, EventArgs e)
{
}
private void mnuFileExit_Click_1(object sender, EventArgs e)
{
this.Close();
}
private void mnuFilePrint_Click_1(object sender, EventArgs e)
{
// Call the print process by calling the Print method
printDocument1.Print();
}
private void mnuFilePrintPreview_Click_1(object sender, EventArgs e)
{
// Begin print preview by assigning PrintDocument
printPreviewDialog1.Document = printDocument1;
printPreviewDialog1.ShowDialog();
}
private void mnuEditRemove_Click_1(object sender, EventArgs e)
{
// Remove the selected book from the list
if (cboBooks.SelectedIndex != -1)
{
cboBooks.Items.RemoveAt(cboBooks.SelectedIndex);
}
else
{
MessageBox.Show("First select a book to remove",
"No selection made", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
private void mnuEditClear_Click_1(object sender, EventArgs e)
{
// Clear the book list
DialogResult responseDialogResult;
responseDialogResult = MessageBox.Show("Clear the book list?",
"Clear book list", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (responseDialogResult == DialogResult.Yes)
{
cboBooks.Items.Clear();
}
}
private void mnuEditCount_Click_1(object sender, EventArgs e)
{
// Display a count of the books on the list
MessageBox.Show("The number of book types is " + cboBooks.Items.Count.ToString());
}
private void mnuHelpAbout_Click_1(object sender, EventArgs e)
{
frmAbout frmAboutObj = new frmAbout();
frmAboutObj.ShowDialog(); //.ShowDialog displays as a Modal Form
}
}
}
同样，一些代码是生成的，因为它可以解决问题，所以如果它混乱或不必要地长，我会道歉。请帮忙？谢谢。
答案 0 :(得分：0)
摆脱frmAbout.ShowDialog（）
中的throw new NotImplementedException();
答案 1 :(得分：0)
我决定从头开始重新使用我的大部分代码。问题是我添加了＆＃34;关于表格＆＃34;不正确;我应该选择项目＆gt;添加表单而不是启动一个全新的项目。我最初也是以＃34;关于Form＆＃34;因为我误读了指示。