using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace Student
{
public partial class GrdQry : Form
{
public GrdQry()
{
InitializeComponent();
}
private string Qrystrconn;
private string Qryconnstr = "Data Source=WWW-F9EEA54BDCA;Initial Catalog=STUDENT;User ID=sa;Pwd=jxlsqd;Integrated Security=False";
private SqlConnection Qrysqlconn;
private SqlDataAdapter Qrysqlda;
private SqlCommandBuilder Qrysqlcomm;
private DataSet Qrymakset = new DataSet(); private void 成绩查询_Load(object sender, EventArgs e)
{
DataSet UpdStudClassset = new DataSet();
Qrystrconn = " select COURSE from MARK";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
UpdStudClassset.Clear(); Qrysqlda.Fill(UpdStudClassset, "MARK");
for (int i = 0; i < UpdStudClassset.Tables[0].Rows.Count; i++)
{
Makcls.Items.Add(UpdStudClassset.Tables[0].Rows[i][0]);
}
Makcls.SelectedIndex = 0;
}
private void button4_Click(object sender, EventArgs e)
{
int row = this.Datgr.CurrentCell.RowNumber;
this.Datgr.CurrentCell = new DataGridCell(row + 1, 0);
if (Qrymakset.HasChanges())
{
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(this.Qrystrconn, this.Qrysqlconn);
Qrysqlcomm = new SqlCommandBuilder(Qrysqlda);
// this.Update(Qrymakset.GetChanges(), "MARK");
MessageBox.Show("修改成功!");
}
} private void button5_Click(object sender, EventArgs e)
{
int rowNumber = this.Datgr.CurrentCell.RowNumber;
this.Qrymakset.Tables["MARK"].Rows[rowNumber].Delete();
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter("", this.Qrysqlconn);
Qrysqlcomm = new SqlCommandBuilder(Qrysqlda);
Qrysqlda.Update(this.Qrymakset.GetChanges(), "MARK");
MessageBox.Show("删除成功!");
}
private void button1_Click(object sender, EventArgs e)
{
//try
//{
Qrystrconn = "select * from MARK where NAME =" + "'" + this.Maknam.Text.ToString().Trim() + "'";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
Qrymakset.Clear(); Qrysqlda.Fill(Qrymakset, "MARK");
Datgr.DataSource = Qrymakset.Tables[0];
//}
//catch
//{
// MessageBox.Show("信息检索失败");
// }
}
private void button2_Click(object sender, EventArgs e)
{
DataSet Qrymakset = new DataSet();
Qrystrconn = "select * from MARK where COURSE =" + "'" + this.Makcls.Text.ToString().Trim() + "'";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
Qrymakset.Clear(); Qrysqlda.Fill(Qrymakset, "MARK");
Datgr.DataSource = Qrymakset.Tables[0];
} 能运行 但点删除的时候会提示:未将对象引用设置到对象的实例。 未处理NullReferenceException! 各位帮忙看看啊
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace Student
{
public partial class GrdQry : Form
{
public GrdQry()
{
InitializeComponent();
}
private string Qrystrconn;
private string Qryconnstr = "Data Source=WWW-F9EEA54BDCA;Initial Catalog=STUDENT;User ID=sa;Pwd=jxlsqd;Integrated Security=False";
private SqlConnection Qrysqlconn;
private SqlDataAdapter Qrysqlda;
private SqlCommandBuilder Qrysqlcomm;
private DataSet Qrymakset = new DataSet(); private void 成绩查询_Load(object sender, EventArgs e)
{
DataSet UpdStudClassset = new DataSet();
Qrystrconn = " select COURSE from MARK";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
UpdStudClassset.Clear(); Qrysqlda.Fill(UpdStudClassset, "MARK");
for (int i = 0; i < UpdStudClassset.Tables[0].Rows.Count; i++)
{
Makcls.Items.Add(UpdStudClassset.Tables[0].Rows[i][0]);
}
Makcls.SelectedIndex = 0;
}
private void button4_Click(object sender, EventArgs e)
{
int row = this.Datgr.CurrentCell.RowNumber;
this.Datgr.CurrentCell = new DataGridCell(row + 1, 0);
if (Qrymakset.HasChanges())
{
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(this.Qrystrconn, this.Qrysqlconn);
Qrysqlcomm = new SqlCommandBuilder(Qrysqlda);
// this.Update(Qrymakset.GetChanges(), "MARK");
MessageBox.Show("修改成功!");
}
} private void button5_Click(object sender, EventArgs e)
{
int rowNumber = this.Datgr.CurrentCell.RowNumber;
this.Qrymakset.Tables["MARK"].Rows[rowNumber].Delete();
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter("", this.Qrysqlconn);
Qrysqlcomm = new SqlCommandBuilder(Qrysqlda);
Qrysqlda.Update(this.Qrymakset.GetChanges(), "MARK");
MessageBox.Show("删除成功!");
}
private void button1_Click(object sender, EventArgs e)
{
//try
//{
Qrystrconn = "select * from MARK where NAME =" + "'" + this.Maknam.Text.ToString().Trim() + "'";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
Qrymakset.Clear(); Qrysqlda.Fill(Qrymakset, "MARK");
Datgr.DataSource = Qrymakset.Tables[0];
//}
//catch
//{
// MessageBox.Show("信息检索失败");
// }
}
private void button2_Click(object sender, EventArgs e)
{
DataSet Qrymakset = new DataSet();
Qrystrconn = "select * from MARK where COURSE =" + "'" + this.Makcls.Text.ToString().Trim() + "'";
Qrysqlconn = new SqlConnection(Qryconnstr);
Qrysqlda = new SqlDataAdapter(Qrystrconn, Qrysqlconn);
Qrymakset.Clear(); Qrysqlda.Fill(Qrymakset, "MARK");
Datgr.DataSource = Qrymakset.Tables[0];
} 能运行 但点删除的时候会提示:未将对象引用设置到对象的实例。 未处理NullReferenceException! 各位帮忙看看啊
解决方案 »
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然后 Qrysqlda.Update(, ); 面的2个参数对比下!你看看问题是出在这里吗?