GetChanges问题 高手们 快来啊！

Question

        public virtual void Save()
        {
            DataSet dsChanges = (DataSet)ds.GetChanges();
            if (dsChanges == null)
            {
                MessageBox.Show("数据没有任何修改", "保存提示");
                return;
            }
        }        private void button1_Click(object sender, EventArgs e)
        {
            DataSet dsChanges = (DataSet)ds.GetChanges();
            if (dsChanges == null)
            {
                MessageBox.Show("数据没有任何修改", "保存提示");
                return;
            }
        }同样的修改一条数据  我在按钮里的代码就可以得到dataset的变化，从而保存       可是我写在函数里在别处调用就不行，得到的dsChanges 是null！  代码一样的啊我试着在函数里调用按钮的点击事件  也不行！

Answer 1

建议你在button1_Click中调用Save()看看是不是还这样啊因为有可能在你调用Save()以前已经导致ds做了改变了。

Answer 2

public virtual void Save() 
        { 
            DataSet dsChanges = (DataSet)ds.GetChanges(); 
            if (dsChanges == null) 
            { 
                MessageBox.Show("数据没有任何修改", "保存提示"); 
                return; 
            } 
        } 
你这个是虚方法啊！

Answer 3

ds.GetChanges();之前是否已经ds.AcceptChanges();

Answer 4

public void save(dataset ds)
{
  DataSet dsChanges = ds.GetChanges(); 
  if (dsChanges == null) 
  }
  MessageBox.Show("数据没有任何修改", "保存提示"); 
  } 
}
试试这个

Answer 5

不是虚函数也不行啊！ 并且我在之前没有AcceptChanges

Answer 6

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;using ControlDataBase;
using Treecheck;
using Treebind;
using MyDgvsave;
using System.Collections;
using MyDgvdel;namespace atuomenu.Win
{
    
    public partial class FrmbaseFormmodu : Form
    {        public DataSet ds = new DataSet();
        DataTable dt = new DataTable();
        public FrmbaseFormmodu()
        {
            InitializeComponent();
        }        private void FrmbaseFormmodu_Load(object sender, EventArgs e)
        {
            Init();            dataGridView1.AllowUserToAddRows = false;
            dataGridView1.ColumnHeadersDefaultCellStyle.BackColor = Color.FromArgb(160, 206, 255);
            GridCss.Grid_RGb(dataGridView1);
            
        }        //初始化datagridview
        private void Init()
        {
            string str="select fqueryid,fmoduleid,fnote,fcol,fcolname,fcolwidth,ftablename,fkeycol,"+
                        "freturn,forder,fcond,fkeyname,fvisible from t_sys_query "+ 
                        "where fpagesize is null order by fmoduleid,fqueryid ";
           
            ds = DataBase.Query(str, "gridview");
            dt=ds.Tables["gridview"];            dataGridView1.DataSource = dt;            dataGridView1.Columns[0].HeaderText = "查询代码";
            dataGridView1.Columns[1].HeaderText = "菜单代码";
            dataGridView1.Columns[2].HeaderText = "窗体名称";
            dataGridView1.Columns[3].HeaderText = "包含列";
            dataGridView1.Columns[4].HeaderText = "包含列名";
            dataGridView1.Columns[5].HeaderText = "列宽";
            dataGridView1.Columns[6].HeaderText = "表名";
            dataGridView1.Columns[7].HeaderText = "查询条件对应值";
            dataGridView1.Columns[8].HeaderText = "返回列";
            dataGridView1.Columns[9].HeaderText = "排序列";
            dataGridView1.Columns[10].HeaderText = "筛选条件";
            dataGridView1.Columns[11].HeaderText = "查询条件对应内容";
            dataGridView1.Columns[12].HeaderText = "是否可用";
           
        }        public virtual void ADD()
        {
            //add
            DataSet dsChanges = (DataSet)ds.GetChanges();
            if (dsChanges == null)
            {
                if (dataGridView1.DataSource != null)
                {
                    BindingSource bd = new BindingSource(ds, "gridview");                    this.dataGridView1.DataSource = bd;
                    DataRow dr = this.dt.NewRow();
                    this.dt.Rows.Add(dr);                    dataGridView1.CurrentCell = dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells[1];
                }
            }
            else
            {
                MessageBox.Show("请保存当前记录后再新增行！");
            }
        }
        private void BindGridData()
        {
            string strsql = "select fqueryid,fmoduleid,fnote,fcol,fcolname,fcolwidth,ftablename,fkeycol," +
                        "freturn,forder,fcond,fkeyname,fvisible from t_sys_query " +
                        "where fpagesize is null order by fmoduleid,fqueryid ";
            ds = DataBase.Query(strsql, "gridview");            dt = ds.Tables["gridview"];
            this.dataGridView1.DataSource = dt;
        }
        public void Save()
        {
            //save
            int aa = dataGridView1.Rows.Count;            string strsql = "select fqueryid,fmoduleid,fnote,fcol,fcolname,fcolwidth,ftablename,fkeycol," +
                        "freturn,forder,fcond,fkeyname,fvisible from t_sys_query ";
            Dgvsave.datagridviewsave(ds, strsql);
            BindGridData();
            this.dataGridView1.AllowUserToAddRows = false;        }        private void button1_Click(object sender, EventArgs e)
        {
            DataSet dsChanges = (DataSet)ds.GetChanges();
            if (dsChanges == null)
            {
                MessageBox.Show("数据没有任何修改", "保存提示");
                return;
            }
            //save
            int aa = dataGridView1.Rows.Count;            string strsql = "select fqueryid,fmoduleid,fnote,fcol,fcolname,fcolwidth,ftablename,fkeycol," +
                        "freturn,forder,fcond,fkeyname,fvisible from t_sys_query ";
            Dgvsave.datagridviewsave(ds, strsql);
            BindGridData();
            this.dataGridView1.AllowUserToAddRows = false;
        }
        public virtual void Delete()
        {
            //del
            string strsql = "select fqueryid,fmoduleid,fnote,fcol,fcolname,fcolwidth,ftablename,fkeycol," +
                        "freturn,forder,fcond,fkeyname,fvisible from t_sys_query ";
            Dgvdel.datagridviewdel(this.dataGridView1);
            Dgvsave.datagridviewsave(ds, strsql);
        }    }
}

Answer 7

 button1_Click  可以保存     Save() 不行

Answer 8

在这个窗口里再加个按钮来调save  就可以    但在mid框架的按钮来调这个窗体的save就不行