代码：
namespace MySchool
{
public partial class StudentChangeForm : Form
{
public StudentChangeForm()
{
InitializeComponent();
}
private void StudentChangeForm_Load(object sender, EventArgs e)
{
// 加载数据对象
try
{
SqlCommand command = new SqlCommand("select StudentId, StudentName, StudentNO, Sex, StudentIDNO,Major,Phone,Address,PostalCode from Student order by StudentId", DBHelper.connection);
DBHelper.connection.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
DataGridViewRowCollection dgrc = dgv.Rows;
Object[] objs = new Object[9];
objs[0] = reader["StudentId"].ToString();
objs[1] = reader["StudentName"].ToString();
objs[2] = reader["StudentNO"].ToString();
objs[3] = reader["Sex"].ToString();
objs[4] = reader["StudentIDNO"].ToString();
objs[5] = reader["Major"].ToString();
objs[6] = reader["Phone"].ToString();
objs[7] = reader["Address"].ToString();
objs[8] = reader["PostalCode"].ToString();
dgrc.Add(objs);
}
reader.Close();
}
catch (Exception ex)
{
MessageBox.Show("登录失败：" + ex.ToString(), "提示");
}
finally
{
DBHelper.connection.Close();
}
CenterToScreen();
dgv.ClearSelection();
dgv.MultiSelect = false;
dgv.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
}
private void dgv_RowStateChanged(object sender, DataGridViewRowStateChangedEventArgs e)
{
if (e.StateChanged == DataGridViewElementStates.Selected)
{
DataGridViewRow row = e.Row;
DataGridViewCellCollection cells = row.Cells;
text1.Text = cells[0].Value.ToString();
text2.Text = cells[1].Value.ToString();
text3.Text = cells[2].Value.ToString();
if (cells[3].Value.ToString().Equals("男")) radioSex.Select();
else radioSex2.Select();
text4.Text = cells[4].Value.ToString();
text5.Text = cells[5].Value.ToString();
text6.Text = cells[6].Value.ToString();
text7.Text = cells[7].Value.ToString();
text8.Text = cells[8].Value.ToString();
}
}
private void dgv_CellClick(object sender, DataGridViewCellEventArgs e)
{
DataGridViewRow row = dgv.Rows[e.RowIndex];
DataGridViewCellCollection cells = row.Cells;
text1.Text = cells[0].Value.ToString();
text2.Text = cells[1].Value.ToString();
text3.Text = cells[2].Value.ToString();
if (cells[3].Value.ToString().Equals("男")) radioSex.Checked = true;
else radioSex2.Checked = true;
text4.Text = cells[4].Value.ToString();
text5.Text = cells[5].Value.ToString();
text6.Text = cells[6].Value.ToString();
text7.Text = cells[7].Value.ToString();
text8.Text = cells[8].Value.ToString();
}
private void button1_Click(object sender, EventArgs e)
{
if (text1.Text.Length == 0)
{
MessageBox.Show("请输入学号！", "提示");
return;
}
if (text2.Text.Length == 0)
{
MessageBox.Show("请输入姓名！", "提示");
return;
}
char sex = radioSex.Checked ? '男' : '女';
// 查询题目信息的sql语句
string sql = "insert into Student ( StudentId, StudentName, StudentNO, Sex, StudentIDNO,Major,Phone,Address,PostalCode) values ('" + text1.Text;
sql += "', '" + text2.Text + "','" + text3.Text + "','"+ sex + "', '" + text4.Text + "', '" + text5.Text + "', '" + text6.Text + "', '" + text7.Text + "', '" + text8.Text + "');";
try
{
SqlCommand command = new SqlCommand(sql, DBHelper.connection);
DBHelper.connection.Open();
command.ExecuteNonQuery();
MessageBox.Show("添加成功！", "提示");
DataGridViewRowCollection dgrc = dgv.Rows;
Object[] objs = new Object[5];
objs[0] = text1.Text;
objs[1] = text2.Text;
objs[2] = text3.Text;
objs[3] = sex;
objs[4] = text4.Text;
objs[5] = text5.Text;
objs[6] = text6.Text;
objs[7] = text7.Text;
objs[8] = text8.Text;
int row = dgrc.Add(objs);
dgv.CurrentCell = dgv.Rows[row].Cells[0];
}
catch (Exception ex)
{
MessageBox.Show("添加失败：" + ex.ToString(), "提示");
}
finally
{
DBHelper.connection.Close();
}
}
private void button2_Click(object sender, EventArgs e)
{
DataGridViewRow row = dgv.CurrentRow;
if (row == null)
{
MessageBox.Show("请先选择行对象", "提示");
return;
}
string StudentId = row.Cells[0].Value.ToString();
if (text1.Text.Length == 0)
{
MessageBox.Show("请输入学号！", "提示");
return;
}
if (text2.Text.Length == 0)
{
MessageBox.Show("请输入姓名！", "提示");
return;
}
char sex = radioSex.Checked ? '男' : '女';
// 查询题目信息的sql语句
string sql = String.Format("update Student set StudentId='{0}',StudentName='{1}', StudentNO='{2}', Sex='{3}', StudentIDNO='{4}',Major='{5}',Phone='{6}',Address='{7}',PostalCode='{8}'where StudentId='{9}';",
text1 .Text , text2.Text, text3.Text, sex, text4.Text, text5.Text, text6.Text, text7.Text, text8.Text,StudentId );
try
{
SqlCommand command = new SqlCommand(sql, DBHelper.connection);
DBHelper.connection.Open();
command.ExecuteNonQuery();
MessageBox.Show("修改成功！", "提示");
row.Cells[0].Value = text1.Text;
row.Cells[1].Value = text2.Text;
row.Cells[2].Value = text3.Text;
row.Cells[3].Value = sex;
row.Cells[4].Value = text4.Text;
row.Cells[5].Value = text5.Text;
row.Cells[6].Value = text6.Text;
row.Cells[7].Value = text7.Text;
row.Cells[8].Value = text8.Text;
}
catch (Exception ex)
{
MessageBox.Show("修改失败：" + ex.ToString(), "提示");
}
finally
{
DBHelper.connection.Close();
}
}
错误页面：一个是无法更新标识列"StudentId",一个是当IDENTITY_INSERT设置为OFF时，不能为表Student中标识列插入显式值
------解决思路----------------------
string sql = String.Format("update Student set StudentId='{0}',StudentName='{1}', StudentNO='{2}', Sex='{3}', StudentIDNO='{4}',Major='{5}',Phone='{6}',Address='{7}',PostalCode='{8}'where StudentId='{9}';",
把套红的干掉。也就是说ID那一列不能往回写
------解决思路----------------------
设置成主键,自动增长,那么它就不能手动修改了,而且你也不应该去修改它,即使你传入的数据和它原来的值一样也不行