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c# - 我可以使用 Combobox 在字体查看器中更改大小和样式吗？

问题描述

#大家好，我在 C# 中遇到了 Forms 的问题，我想制作一个字体查看器，实际上我想制作两个 Combobox 来更改“图形”并以其样式和特定的字体显示相同的字体名称第二个组合框的大小。主要问题是样式和大小不会改变。告诉我任何错误都会很酷:)这是我的代码。#

namespace CodeImage35
{
    class Visualizer : Form
    {
        Label choose; 
        PictureBox picbox; //this is for the text 
        Graphics textm; //the text in PictureBox
        ComboBox fontsm; //font of the text
        ComboBox size; //size of the font
        String fonts; //I used this for get the fonts,maybe never is used


        public Visualizer() //Here is the UI
        {
            this.Width = 600;
            this.Height = 300;
            this.Text = "Visualizer of fonts";

            choose = new Label();
            choose.Size = new Size(100, 20);
            choose.Location = new Point(20, 20);
            choose.Text = "Choose Font:";

            picbox = new PictureBox();
            picbox.Size = new Size(300, 200);
            picbox.Location = new Point(100,150);

            

            fontsm = new ComboBox();
            fontsm.Location = new Point(110, 20);
            fontsm.Size = new Size(350, 20);

            size = new ComboBox();
            size.Location = new Point(480, 20);
            size.Size = new Size(100, 20);

            System.Drawing.Text.InstalledFontCollection fonts = new InstalledFontCollection(); //this         
            //is for the fonts
            

            foreach ( FontFamily style in fonts.Families )//I add them in the combobox here
            {
                fontsm.Items.Add(style.Name);
            }
          

            for( int s = 1; s <= 50; size++ )
            {
                size.Items.Add(s); //I add here the sizes from 1 to 50
            }


            picbox.Paint += new PaintEventHandler(write_in_PictureBox);
            Controls.Add(fontsm);
            Controls.Add(choose);
            Controls.Add(size);
            Controls.Add(picbox);

        }
        void write_in_PictureBox(object sender, PaintEventArgs e)
        {
            
            String text2 = fontsm.Text;
            textm = e.Graphics;
            int x = 0;
            Int32.TryParse(size.Text, out x); //I tried with this function to make string to int for 
                                              //the parameter of "DrawString
            textm.DrawString( text2 , new Font( text2, x ), Brushes.Black, new Point(10, 10) );
        }

    }

    static class MainClass
    {   
        static void Main()
        {
            Visualizer screen1 = new Visualizer(); 
            Application.Run(screen1);
        }
    }
}

标签： c#user-interface

解决方案

要开始修复此编译器错误：

for( int s = 1; s <= 50; size++ )
{
    size.Items.Add(s); //I add here the sizes from 1 to 50
}

要增加的正确变量是s。你也避免从 1 开始，这个值真的太小而无法渲染字体并欣赏结果。从6或8开始应该没问题。除此之外...

为了绘制一个字符串，基于两个组合框的输入，您必须处理SelectedValueChanged事件（或 SelectedIndexChanged）。当用户更改（选择）组合框中的值时，就会发生这些事件。

相反，PaintEventHandler 在绘制控件时发生。请参阅绘画事件。

按照您的示例，您可以将 SelectedValueChanged 事件附加到绘制字符串的方法，就像您在write_in_PictureBox方法中所做的那样。

//put this at the end of the constructor method.
//The event will be triggered on both combobox, allowing the user to see the result of it's selection whatever combobox is edited
fontsm.SelectedValueChanged += (sender, args) => DrawFont();
size.SelectedValueChanged += (sender, args) => DrawFont();

//that's just a method to handle the event
private void DrawFont()
{
    using (var g = picbox.CreateGraphics()) //remember to always dispose a disposable resource
    {
        //clear the area before draw the new string
        g.Clear(DefaultBackColor);
        if (!Int32.TryParse(size.Text, out int x)) x = 12; //if no value is selected for size combobox, use 12 as default
        string text = fontsm.Text;
        g.DrawString(text, new Font(text, x), Brushes.Black, new Point(10, 10)); 
    }
}

顺便说一句...如果您只想显示字体预览...您只需放置一个标签并更改它的文本和字体属性会更容易:)。

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