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  • DBHELPER.CS查、增、删、改例子

    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;
    using System.Data.SqlClient;
    using DevExpress.XtraEditors;
    
    namespace DXApplication5
    {
        public partial class Form1 : DevExpress.XtraEditors.XtraForm
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            //绑定数据表
            private void simpleButton1_Click(object sender, EventArgs e)
            {
                //返回封装的表形式
                //this.gridControl1.DataSource = DBHelper.GetDataTable("select * from myuser");
                //普通表
                this.gridControl1.DataSource = DBHelper.GetDataSet("select * from myuser").Tables[0];
            }
            //清空数据表
            private void simpleButton5_Click(object sender, EventArgs e)
            {
                this.gridControl1.DataSource = null;
            }
    
            /// <summary>
            /// 表示每行生成的时候随绘制这一行数据的时候触发
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="e"></param>
            private void gridView1_CustomDrawRowIndicator(object sender, DevExpress.XtraGrid.Views.Grid.RowIndicatorCustomDrawEventArgs e)
            {
                if (e.Info.IsRowIndicator && e.RowHandle >= 0)//在表格前面加行号
                {
                    e.Info.DisplayText = (e.RowHandle + 1).ToString();
                }
            }
    
            /// <summary>
            /// 表示获取某行中某列的数据
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="e"></param>
            private void gridView1_Click(object sender, EventArgs e)
            {
               
                //当表不为空时获取单元格数据有效
                if (this.gridControl1.DataSource != null)
                {
                    //获取点击的行数
                    int selectedHandle = this.gridView1.GetSelectedRows()[0];
    
                    //得到该行中某列绑定字段的值 
                    this.textEdit1.Text = this.gridView1.GetRowCellValue(selectedHandle, "username").ToString().Trim();
                    this.textEdit2.Text = this.gridView1.GetRowCellValue(selectedHandle, "mygroup").ToString().Trim();
                    this.textEdit3.Text = this.gridView1.GetRowCellValue(selectedHandle, "mystop").ToString().Trim();
                }
            }
    
            //新建一条数据
            private void simpleButton2_Click(object sender, EventArgs e)
            {
                //SQL语句:先查询数据是否已经存在相同的数据
                string SSQL = "select * from myuser where username='" + Convert.ToString(textEdit1.Text.Trim()) + "'";
    
                //使用ExecuteNonQuery指令SELECT查询时不会返回行数,因此查询需要使用ExecuteScalar指令
    
                if (DBHelper.ExecuteScalar(SSQL) == null)
                {
                    string ADDSQL = "insert into myuser(username,mygroup,mystop)  values('" + Convert.ToString(textEdit1.Text.Trim()) + "','" + Convert.ToString(textEdit2.Text.Trim()) + "','" + Convert.ToString(textEdit3.Text.Trim()) + "')";
                    int m = DBHelper.ExecuteNonQuery(ADDSQL);
                    if (m > 0)
                    {
                        //刷新数据表
                        this.gridControl1.DataSource = DBHelper.GetDataTable("select * from myuser");
                    }
                }
                else
                {
                    XtraMessageBox.Show("添加失败,已存在相同数据");
                }
            }
    
            //删除一条数据
            private void simpleButton3_Click(object sender, EventArgs e)
            {
                //SQL语句
                string SQL = "delete from myuser where username='" + Convert.ToString(textEdit1.Text.Trim()) + "'";
                int n = DBHelper.ExecuteNonQuery(SQL);
                if (n > 0)
                {
                    //刷新数据表
                    this.gridControl1.DataSource = DBHelper.GetDataTable("select * from myuser");
                }
                else
                {
                    XtraMessageBox.Show("删除失败");
                }
            }
    
            //修改一条数据
            private void simpleButton4_Click(object sender, EventArgs e)
            {
                //SQL语句
                string SQL = "Update myuser set mygroup='" + textEdit2.Text.Trim() + "',mystop='" + textEdit3.Text.Trim() + "' " + " where username=" + "'" + textEdit1.Text.Trim() + "'";
                int n = DBHelper.ExecuteNonQuery(SQL);
                if (n > 0)
                {
                    //刷新数据表
                    this.gridControl1.DataSource = DBHelper.GetDataTable("select * from myuser");
                }
                else
                {
                    XtraMessageBox.Show("修改失败");
                }
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/Bung/p/14281501.html
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