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2006-10-30 08:40:59 89 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

掌握 Sass 占位符选择器，前端样式复用更高效在前端开发中，我们经常会遇到需要复用样式的情况。传统的 CSS 在样式复用方面存在一些局限性，而 Sass 作为一种强大的 CSS 预处理器，提供了占位符选择器这一特性，能有效解决样式复用的问题。本文的目的就是详细介绍 Sass 占位符选择器，帮助开发者掌握它的使用方法，提高前端样式的复用效率。范围涵盖了占位符选择器的基本概念、原理、实际应用等方面。阅读详情

问大家这样一个问题:
我上传图片的时候,是把图片保存在一个文件夹下的,把它的路径存在数据库中的,现在我要做后台,在删除该图片的路径的同时也要删除文件夹下相对应的图片.求源代码.

...全文

在PLC中将十六进制数据转换为浮点数（通常遵循IEEE 754标准）需要理解数据存储格式，并按以下步骤操作：通过以上步骤，您可以在PLC中实现十六进制到浮点数的转换。T DBD20 // 将数据传送到浮点数变量（如DB1.DBD20）指数位（8位）：实际指数 = 存储值 - 127（偏移量）。：必须确认PLC的存储顺序（大端或小端），否则结果错误。将两个16位寄存器合并为32位数据，需注意。尾数位（23位）：隐含前导1，实际值为。：确保32位数据在寄存器中连续且对齐。符号位（1位）：0表示正，1表示负。：高位寄存器在前（如西门子PLC）。：低位寄存器在前（如三菱FX系列）。，误差因截断导致）。阅读详情

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切换为时间正序

N_ccw 2006-11-01

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在使用的时候当然不能删

song530061187 2006-11-01

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System.IO.File.Delete(文件路径字符串) 我在弄，可是出错，说正在使用图片，不能删除。。郁闷啊。

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
using System.IO;

namespace MapDeleteAndSql
{
/// <summary>
/// Form1 的摘要说明。
/// </summary>
public class main : System.Windows.Forms.Form
{
private static int i = 1;
private static int g = 1;
private static string str;
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.Button button3;
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.Container components = null;

public main()
{
//
// Windows 窗体设计器支持所必需的
//
InitializeComponent();

//
// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
//
}

/// <summary>
/// 清理所有正在使用的资源。
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

#region Windows 窗体设计器生成的代码
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.button3 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// pictureBox1
//
this.pictureBox1.Location = new System.Drawing.Point(16, 16);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(280, 184);
this.pictureBox1.TabIndex = 0;
this.pictureBox1.TabStop = false;
//
// button1
//
this.button1.Location = new System.Drawing.Point(16, 224);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(64, 32);
this.button1.TabIndex = 1;
this.button1.Text = "上一张";
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// button2
//
this.button2.Location = new System.Drawing.Point(120, 224);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(64, 32);
this.button2.TabIndex = 2;
this.button2.Text = "一下张";
this.button2.Click += new System.EventHandler(this.button2_Click);
//
// button3
//
this.button3.Location = new System.Drawing.Point(216, 224);
this.button3.Name = "button3";
this.button3.Size = new System.Drawing.Size(64, 32);
this.button3.TabIndex = 3;
this.button3.Text = "删除";
this.button3.Click += new System.EventHandler(this.button3_Click);
//
// main
//
this.AutoScaleBaseSize = new System.Drawing.Size(7, 16);
this.ClientSize = new System.Drawing.Size(312, 278);
this.Controls.Add(this.button3);
this.Controls.Add(this.button2);
this.Controls.Add(this.button1);
this.Controls.Add(this.pictureBox1);
this.Font = new System.Drawing.Font("宋体", 10.5F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(134)));
this.Name = "main";
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
this.Text = "删除SQL中的图片";
this.Load += new System.EventHandler(this.main_Load);
this.ResumeLayout(false);

}
#endregion

/// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
Application.Run(new main());
}

private void main_Load(object sender, System.EventArgs e)
{
SqlConnection conn = new SqlConnection("server = (local);Integrated Security = SSPI; Database = song;");
SqlCommand comm = new SqlCommand("SELECT path FROM map",conn);
try
{
conn.Open();
SqlDataReader thisReader = comm.ExecuteReader();
thisReader.Read();
str = thisReader[0].ToString();
this.pictureBox1.Image=Image.FromFile(thisReader[0].ToString());
while ( thisReader.Read() )
{
g+=1;
}
thisReader.Close();
//MessageBox.Show(g.ToString());
}
catch( SqlException ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
conn.Close();
}
}
private void Showmap(int i)
{
if ( i >= 0 )
{
SqlConnection conn = new SqlConnection("server = (local);Integrated Security = SSPI; Database = song;");
SqlCommand comm = new SqlCommand("SELECT path FROM map",conn);
try
{
conn.Open();
SqlDataReader thisReader = comm.ExecuteReader();
int k = 0;
while( thisReader.Read() )
{
k++;
if ( k == i)
{
str = thisReader.GetString(0);
//MessageBox.Show(str);
this.pictureBox1.Image=Image.FromFile(str);
break;
}
}
}
catch( SqlException ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
conn.Close();
}
}
}
private void button1_Click(object sender, System.EventArgs e)
{
if ( i> 1 )
{
i-=1;
//MessageBox.Show(i.ToString());
Showmap(i);
}
}

private void button2_Click(object sender, System.EventArgs e)
{
if ( i < g )
{
i+=1;
//MessageBox.Show(i.ToString());
Showmap(i);
}
}
private void button3_Click(object sender, System.EventArgs e)
{
SqlConnection conn = new SqlConnection("server = (local);Integrated Security = SSPI; Database = song;");
//MessageBox.Show(str);
string ss = "DELETE FROM map WHERE path="+str.Trim().ToString();
MessageBox.Show(ss.ToString());
SqlCommand comm = new SqlCommand(ss,conn);
try
{
conn.Open();
//comm.ExecuteNonQuery();
g--;
}
catch( SqlException ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
conn.Close();
}
if( g > 0 )
{

if ( i < g )
{
i+=1;
//MessageBox.Show(i.ToString());
Showmap(i);
}

}
System.IO.File.Delete(str);
}

}
}

刚刚学习 .NET 学得乱七八糟请大家多多指教。。。

大选 2006-11-01

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