C＃| Graphics.DrawLine()方法|套装– 1

Graphics.DrawLine()方法用于绘制一条连接由坐标对指定的两个点的线。此方法的重载列表中有4种方法，如下所示：

• DrawLine(Pen，PointF，PointF)方法
• DrawLine(Pen，Int32，Int32，Int32，Int32)方法
• DrawLine(笔，单，单，单，单)方法
• DrawLine(笔，点，点)方法

在这里，我们将讨论前两种方法。

DrawLine(Pen，PointF，PointF)方法

此方法用于绘制从一组指定的点到一组指定的点的线形。它需要一个PointF变量，该变量由(x，y)点组成。

句法：

public void DrawLine (System.Drawing.Pen pen, System.Drawing.PointF pt1, System.Drawing.PointF pt2);

参数：

• 笔：笔确定线条的颜色，宽度和样式。
• pt1：将(x，y)坐标定义为初始点的PointF变量。
• pt2：将(x，y)坐标定义为最终点的PointF变量。

例外：如果笔为null，则此方法将提供ArgumentNullexception。

例子：

// C# program to demonstrate the 
// DrawLine(Pen, PointF, PointF) Method
using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;
  
namespace GFG {
  
class PrintableForm : Form {
  
    public static void Main()
    {
        Application.Run(new PrintableForm());
    }
  
    public PrintableForm()
    {
        ResizeRedraw = true;
    }
    protected override void OnPaint(PaintEventArgs pea)
    {
        // Defines pen
        Pen pen = new Pen(ForeColor);
  
        // Defines the both points to connect
        // pt1 is (30.0, 30.0) which represents (x1, y1)
        PointF pt1 = new PointF(30.0F, 30.0F);
  
        // pt2 is (200.0, 300.0) which represents (x2, y2)
        PointF pt2 = new PointF(200.0F, 300.0F);
  
        // Draws the line
        pea.Graphics.DrawLine(pen, pt1, pt2);
    }
}
}

输出：

DrawLine(Pen，Int32，Int32，Int32，Int32)方法

此方法用于绘制线形式的一组指定坐标，这些坐标以x1，y1，x2，y2形式给出，这些坐标都是离散的。

句法：

public void DrawLine (System.Drawing.Pen pen, int x1, int y1, int x2, int y2);

参数：

• pen ：Pen确定线条的颜色，宽度和样式。
• x1 ：第一个点的横坐标。
• y1 ：第一点的纵坐标。
• x2 ：第二点的横坐标。
• y2 ：第二点的纵坐标。

例外：如果笔为null，则此方法将提供ArgumentNullexception。

范例1：

// C# program to draw a cross using the
// DrawLine(Pen, Int32, Int32, Int32,
// Int32) Method
using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;
  
namespace GFG {
  
class PrintableForm : Form {
  
    public static void Main()
    {
        Application.Run(new PrintableForm());
    }
  
    public PrintableForm()
    {
        ResizeRedraw = true;
    }
  
    protected override void OnPaint(PaintEventArgs pea)
    {
        // Defines the pen
        Pen pen = new Pen(ForeColor);
  
        // To draw a cross we need to make 2 
        // diagonals from top-left to the 
        // bottom-right and top-right to the 
        // bottom-left to calculate these 
        // coordinates we would take help of 
        // our screen size top-left = (0, 0)
        // bottom-right = (ClientSize.Width - 1,
        // ClientSize.Height - 1)
        // top-right = (ClientSize.Width - 1, 0)
        // bottom-left = (0, ClientSize.Height - 1)
        pea.Graphics.DrawLine(pen, 0, 0, ClientSize.Width - 1,
                                       ClientSize.Height - 1);
  
        pea.Graphics.DrawLine(pen, ClientSize.Width - 1, 0, 0,
                                       ClientSize.Height - 1);
    }
}
}

输出：

范例2：

// C# program to Create a 8x8 square board
// using // DrawLine(Pen, Int32, Int32, Int32,
// Int32) Method
using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;
  
namespace GFG {
  
class PrintableForm : Form {
  
    public static void Main()
    {
        Application.Run(new PrintableForm());
    }
  
    public PrintableForm()
    {
        ResizeRedraw = true;
    }
  
    protected override void OnPaint(PaintEventArgs pea)
    {
        // Define Pen
        Pen pen = new Pen(ForeColor);
  
        // loop for all 7 horizontal lines to draw
        for (int i = 0; i < 7; i++) 
        {
            // Taking Block size to be 30x30
            // So width and height will be 30*8=240
            pea.Graphics.DrawLine(pen, i * 30, 0, i * 30, 240);
        }
  
        // loop for all 7 horizontal lines to draw
        for (int i = 0; i < 7; i++) 
        {
            pea.Graphics.DrawLine(pen, 0, i * 30,
                                    240, i * 30);
        }
    }
}
}

输出：