c# - 如何在打印之前预先测量字符串？

Question

您好，我正在学习使用 C# VS 2010 EE 进行编程，并且正在申请填​​写预印表格。这种形式在不同的坐标中有几个地方。纸上的三个盒子是多行 5” W x 2” H 盒子。

我已经为纸质表单上的每个位置创建了带有一个 TextBox 的 Windows 表单。

问题是，在这些多行文本框中输入信息时，我需要知道纸上还有多少行可以输入更多文本，以及何时停止输入，因为预印框中没有更多可用空间.

我做了很多搜索，但我发现的所有内容都是关于屏幕上的测量，与纸上的最终结果不符。

换句话说，我需要知道如何在文本框中输入字符串时找出纸上的字符串尺寸，并将其与预打印表单上的可用空间进行比较，以便我可以在它之前停下来越过纸上方框的底部边界。

纸上的第一个框宽 5 英寸，高 2 英寸，从“new RectangleF(60.0F, 200.0F, 560.0F, 200.0F)”开始。我知道这些数字是百分之一英寸。

所有这些，考虑到我无法通过字符数量限制文本框，因为并非所有字符都占用相同的空间，例如 H != I; M != l; 等

预先感谢您的帮助。 今天 2011 年 9 月 5 日，根据您的意见和建议，我更改了代码以使用 Graphics.MeasureString 。

这是我现在拥有的带有 Graphics.MeasureString 且只有一个 richTextBox 的代码: 在 printDocument1_PrintPage 事件中运行良好，但我不知道如何在 richTextBox1_TextChanged 事件中运行。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Printing;//Needed for the PrintDocument()
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Printing
{
  public partial class Form1 : Form
  {
    private Font printFont1;
    string strPrintText;

    public Form1()
    {
      InitializeComponent();
    }

    private void cmdPrint_Click(object sender, EventArgs e)
    {
      try
      {
        PrintDocument pdocument = new PrintDocument();
        pdocument.PrintPage += new PrintPageEventHandler
        (this.printDocument1_PrintPage);
        pdocument.Print();
      }
      catch (Exception ex)
      {
        MessageBox.Show(ex.Message);
      }
    }

    public void printDocument1_PrintPage (object sender,
      System.Drawing.Printing.PrintPageEventArgs e)
    {
      strPrintText = richTextBox1.Text.ToString();
      printFont1 = new Font("Times New Roman", 10); //I had to remove this line from the btnPrintAnexo1_Click
      Graphics g = e.Graphics;
      StringFormat format1 = new StringFormat();
      RectangleF rectfText;
      int iCharactersFitted, iLinesFitted;

      rectfText = new RectangleF(60.0F, 200.0F, 560.0F, 200.0F);
      // The following e.Graphics.DrawRectangle is
      // just for debuging with printpreview
      e.Graphics.DrawRectangle(new Pen(Color.Black, 1F),
        rectfText.X, rectfText.Y, rectfText.Width, rectfText.Height);

      format1.Trimming = StringTrimming.Word; //Word wrapping

      //The next line of code "StringFormatFlags.LineLimit" was commented so the condition "iLinesFitted > 12" could be taken into account by the MessageBox
// Use next line of code if you don't want to show last line, which will be clipped, in rectangleF
      //format1.FormatFlags = StringFormatFlags.LineLimit;

      //Don't use this next line of code. Some how it gave me a wrong linesFilled
      //g.MeasureString(strPrintText, font, rectfFull.Size, 
      //StringFormat.GenericTypographic, out iCharactersFitted, out iLinesFilled);

      //Use this one instead:
      //Here is where we get the quantity of characters and lines used 
      g.MeasureString(strPrintText, printFont1, rectfText.Size, format1, out iCharactersFitted, out iLinesFitted);

      if (strPrintText.Length == 0)
      {
        e.Cancel = true;
        return;
      }
      if (iLinesFitted > 12)
      {
        MessageBox.Show("Too many lines in richTextBox1.\nPlease reduce text entered.");
        e.Cancel = true;
        return;
      }

      g.DrawString(strPrintText, printFont1, Brushes.Black, rectfText, format1);
      g.DrawString("iLinesFilled = Lines in the rectangle: " + iLinesFitted.ToString(), printFont1, Brushes.Black,
        rectfText.X, rectfText.Height + rectfText.Y);
      g.DrawString("iCharactersFitted = Characters in the rectangle: " + iCharactersFitted.ToString(), printFont1, Brushes.Black,
        rectfText.X, rectfText.Height + rectfText.Y + printFont1.Height);
    }

    private void richTextBox1_TextChanged(object sender, EventArgs e)
    {
      //***I don’t know what to type here.*** 

        if (iLinesFitted == 13)
        {
            MessageBox.Show("Too many lines in richTextBox1.\nPlease erase some characters.");
        }
    }

      private void cmdPrintPreview_Click(object sender, EventArgs e)
    {
      printPreviewDialog1.ShowDialog();
    }

    private void printDocument1_BeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
    {
//      strPrintText = richTextBox1.Text;
    }
  }
}

Answer 1

我认为这就是您所追求的。

MeasureString(...)

请确保您的图形对象是 PrintDocument。

using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;

namespace GraphicsHandler
{
    public partial class Form1 : Form
    {
        public Form1()
        {
           InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            // Check the width of the text whenever it is changed.
            if (checkTextWillFit(textBox1.Text) == true)
            {
                 MessageBox.Show("Entered test is too wide, please reduce the number of characters.");
            }
        }

        private bool checkTextWillFit(string enteredText)
        {
            // Create a handle to the graphics property of the PrintPage object
            Graphics g = pd.PrinterSettings.CreateMeasurementGraphics();
            // Set up a font to be used in the measurement
            Font myFont = new Font("Arial", 12, FontStyle.Regular, GraphicsUnit.Millimeter);
            // Measure the size of the string using the selected font
            // Return true if it is too large
            if (g.MeasureString(enteredText, myFont).Width > 100)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        PrintDocument pd = null;

        private void Form1_Load(object sender, EventArgs e)
        {
            // Initialise the print documnet used to render the printed page
            pd = new PrintDocument();
            // Create the event handler for when the page is printed
            pd.PrintPage += new PrintPageEventHandler(pd_PrintPage);
        }

        void pd_PrintPage(object sender, PrintPageEventArgs e)
        {
            // Page printing logic here            
        }
    } 
}