求助,怎么通过combobox控件来修改richtextbox的字体大小?

[琴弦欲奏]

我正在编辑一个简单的文本编辑器
想要用combobox这个控件弄一些数字上去
然后点击可以改变richtextbox文本框上的字体大小
就好像QQ聊天对话框哪里的那种
给定数字,然后修改文字的大小
这个要怎么弄?
我是C#菜鸟
希望给位大侠回答能详细点
谢谢

[亲爱的-爹爹]

哥我妥协了，Font.size为常量不能就这么改

[亲爱的-爹爹]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
for (int i = 1; i < 11; i++)
{
comboBox1.Items.Add(i * 8);
}
}

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{

richTextBox1.Font = ChangeFontSize(richTextBox1.Font, int.Parse(this.comboBox1.Items[comboBox1.SelectedIndex].ToString()), GraphicsUnit.Pixel);
}

static public Font ChangeFontSize(Font font, float fontSize, GraphicsUnit unit)
{
if (font != null)
{
float currentSize = font.Size;
if (currentSize != fontSize)
{
font = new Font(font.Name, fontSize,
font.Style, unit,
font.GdiCharSet, font.GdiVerticalFont);
}
}
return font;
}
}
}

[亲爱的-爹爹]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            for (int i = 1; i < 11; i++)
            {
                comboBox1.Items.Add(i * 8);
            }
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

            richTextBox1.Font = ChangeFontSize(richTextBox1.Font, int.Parse(this.comboBox1.Items[comboBox1.SelectedIndex].ToString()), GraphicsUnit.Pixel);
        }

        static public Font ChangeFontSize(Font font, float fontSize, GraphicsUnit unit)
        {
            if (font != null)
            {
                float currentSize = font.Size;
                if (currentSize != fontSize)
                {
                    font = new Font(font.Name, fontSize,
                        font.Style, unit,
                        font.GdiCharSet, font.GdiVerticalFont);
                }
            }
            return font;
        }
    }
}

[laj0600310219]

C#里面本身就自带有实现调节richtextbox控件字体大小的类，如下：

   FontDialog fd = new FontDialog();//字体框
            DialogResult d = fd.ShowDialog();//显示
            if (d.Equals(DialogResult.OK))
            {
                if (rich_Input.SelectedText.Length == 0)//如果未选定，那么就修改全部
                    rich_Input.Font = fd.Font;
                else
                    //修改选定的文本
                    rich_Input.SelectionFont = fd.Font;
            }

[laj0600310219]

还有下面这个是实现调整字体颜色的，一并给你贴出来吧，或许你也会用到：

    ColorDialog MyDialog = new ColorDialog();
            // Keeps the user from selecting a custom color.
            MyDialog.AllowFullOpen = false;
            // Allows the user to get help. (The default is false.)
            MyDialog.ShowHelp = true;
            // Sets the initial color select to the current text color.
            MyDialog.Color = rich_Input.ForeColor;

            // Update the text box color if the user clicks OK 
            if (MyDialog.ShowDialog() == DialogResult.OK)
                rich_Input.ForeColor = MyDialog.Color;