我的错误很简单，但对我来说很难解决，因为我的知识并不好。这是当我通过单击AddStudent Addbutton记录输入记录然后我删除的记录，如记录StudentID = 1，FirstName = Raju，LastName = Abbasi
再次删除后再按保存更改，然后再次尝试使用ID = 1表示输入ID = 1的记录，我已删除并记录StudentID = 1，FirstName = Ram，LastName = Rakish。然后发生错误
private static SqlDataAdapter CreateSutdentDataAdapter()
{
string gettSQL = "SELECT * FROM Student";
string insertSQL = "SET IDENTITY_INSERT Student ON;INSERT INTO Student(StudentID, FirstName,LastName,Gender,GPA,MyImage)" +
"VALUES (@StudentID,@FirstName,@LastName,@Gender,@GPA,@MyImage);SET IDENTITY_INSERT Student OFF";
string updateSQL = "UPDATE Student SET FirstName=@FirstName,LastName=@LastName ,Gender=@Gender, MyImage=@MyImage," +
" GPA=@GPA WHERE StudentID=@StudentID";
string deleteSQL = "DELETE FROM Student WHERE StudentID=@StudentID";
SqlDataAdapter dataAdapter = new SqlDataAdapter();
dataAdapter.SelectCommand = new SqlCommand(gettSQL, ConnectionManager.GetConnection());
dataAdapter.InsertCommand = new SqlCommand(insertSQL, ConnectionManager.GetConnection());
dataAdapter.InsertCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID";
dataAdapter.InsertCommand.Parameters.Add("@FirstName", SqlDbType.VarChar,25 ).SourceColumn = "FirstName";
dataAdapter.InsertCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 25 ).SourceColumn = "LastName";
dataAdapter.InsertCommand.Parameters.Add("@Gender", SqlDbType.VarChar ,1).SourceColumn = "Gender";
dataAdapter.InsertCommand.Parameters.Add("@GPA", SqlDbType.Float ).SourceColumn = "GPA";
dataAdapter.InsertCommand.Parameters.Add("@MyImage", SqlDbType.VarBinary).SourceColumn = "MyImage";
dataAdapter.UpdateCommand = new SqlCommand(updateSQL, ConnectionManager.GetConnection());
dataAdapter.UpdateCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID";
dataAdapter.UpdateCommand.Parameters.Add("@FirstName", SqlDbType.VarChar,25 ).SourceColumn = "FirstName";
dataAdapter.UpdateCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 25 ).SourceColumn = "LastName";
dataAdapter.UpdateCommand.Parameters.Add("@Gender", SqlDbType.VarChar ,1).SourceColumn = "Gender";
dataAdapter.UpdateCommand.Parameters.Add("@GPA", SqlDbType.Float ).SourceColumn = "GPA";
dataAdapter.UpdateCommand.Parameters.Add("@MyImage", SqlDbType.VarBinary).SourceColumn = "MyImage";
dataAdapter.DeleteCommand = new SqlCommand(deleteSQL, ConnectionManager.GetConnection());
dataAdapter.DeleteCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID";
return dataAdapter;
}
private static void DefinestudentTableSchema(DataTable table)
{
DataColumn StudentIDColumn = table.Columns.Add("StudentID", typeof(string));
StudentIDColumn.AllowDBNull = false;
table.PrimaryKey = new DataColumn[] { StudentIDColumn };
DataColumn StudentFirstName = table.Columns.Add("FirstName", typeof(string));
StudentFirstName.MaxLength = 150;
DataColumn StudentLastName = table.Columns.Add("LastName", typeof(string));
StudentLastName.MaxLength = 150;
DataColumn StudentGender = table.Columns.Add("Gender", typeof(string ));
DataColumn StudentGPA = table.Columns.Add("GPA", typeof(string ));
DataColumn StudentImage = table.Columns.Add("MyImage", typeof(Byte[]));
}
private static DataSet CreateStudentTrackerDataSet()
{
DataSet StudentTrackerDataSet = new DataSet();
DataTable StudentTable = StudentTrackerDataSet.Tables.Add("Student");
DefinestudentTableSchema(StudentTable);
return StudentTrackerDataSet;
}
public static DataSet GetData()
{
DataSet StudentTrakerDataSet = CreateStudentTrackerDataSet();
StudentTrakerDataSet.EnforceConstraints = false;
StudentDataAdapter.Fill(StudentTrakerDataSet.Tables["Student"]);
StudentTrakerDataSet.EnforceConstraints = true;
return StudentTrakerDataSet;
}
public AddModifyStudentRecords(DataSet ds, DataRow row)
{
public static void SaveData(ref DataSet changesDataSet)
{
DataSet addedDataSet = changesDataSet.GetChanges(DataRowState.Added);
if (addedDataSet != null)
{
StudentDataAdapter.Update(addedDataSet.Tables["Student"]);
changesDataSet.Merge(addedDataSet); // Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints
}
DataSet modifiedDataSet = changesDataSet.GetChanges(DataRowState.Modified);
if (modifiedDataSet != null)
{
StudentDataAdapter.Update(modifiedDataSet.Tables["Student"]);
changesDataSet.Merge(modifiedDataSet);
}
DataSet deletedDataSet = changesDataSet.GetChanges(DataRowState.Deleted);
if (deletedDataSet != null)
{
StudentDataAdapter.Update(deletedDataSet.Tables["Student"]);
deletedDataSet.Merge(deletedDataSet);
}
这是我的Addmodifyform逻辑，用于添加StudentID
public partial class AddModifyStudentRecords : Form
{
DataSet StudentTrackerDataSet;
DataRow currentRow;
public AddModifyStudentRecords()
{
InitializeComponent();
}
public AddModifyStudentRecords(DataSet ds)
{
InitializeComponent();
StudentTrackerDataSet = ds;
currentRow = null;
}
public AddModifyStudentRecords(DataSet ds, DataRow row)
{
InitializeComponent();
StudentTrackerDataSet = ds;
currentRow = row;
textBox1.Text =currentRow["StudentID"] .ToString();
textBox2.Text = currentRow["FirstName"].ToString();
textBox4.Text = currentRow["LastName"].ToString();
textBox3.Text = currentRow["Gender"].ToString();
textBox5.Text = currentRow["GPA"].ToString();
txtBrowseFile.Text = currentRow["MyImage"].ToString ();
byte[] data = (byte[])currentRow ["MyImage"];
MemoryStream ms = new MemoryStream(data);
pictureBox1.Image = Image.FromStream(ms);
string StudentID = textBox1.Text.ToString();
string StudentFirstName = textBox2.Text.ToString();
string StudentLastName = textBox4.Text.ToString();
string Gender = textBox3.Text.ToString();
string GPA = textBox5.Text.ToString();
Image MyImage = pictureBox1.Image;
DataTable table = StudentTrackerDataSet.Tables["Student"];
if (currentRow == null) {
currentRow = table.NewRow();
currentRow["StudentID"] = textBox1.Text.ToString();
table.Rows.Add(currentRow );
}
currentRow .BeginEdit();
currentRow ["StudentID" ]=StudentID ;
currentRow["FirstName"] = StudentFirstName;
currentRow["LastName"] = StudentLastName;
currentRow["Gender"] = Gender;
currentRow["GPA"] = GPA;
currentRow["MyImage"] = convertToByte(txtBrowseFile.Text);
currentRow.EndEdit();
Close();
}
公共部分类AditStudent：表单 { //创建Class variabl Dataset以跟踪Student private DataSet StudentTrackerDataset;
public AditStudent()
{
InitializeComponent();
dataGridView1.DataError += DataGridView1_DataError;
StudentTrackerDataset = ProjectOfSchool.DataAccessLayer.DAC.GetData();
DataTable StudentTable = StudentTrackerDataset.Tables["Student"];
dataGridView1.DataSource = StudentTable;
//StudentTable.Columns["ID"].AutoIncrement = true;
for (int i = 0; i < dataGridView1.Columns.Count; i++)
if (dataGridView1.Columns[i] is DataGridViewImageColumn)
{
((DataGridViewImageColumn)dataGridView1.Columns[i]).ImageLayout = DataGridViewImageCellLayout.Stretch;
break;
}
}
private void DataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs e)
{
string message = string.Format("Error in {0} columan in row {1}:{2}", e.ColumnIndex, e.RowIndex, e.Exception.Message);
MessageBox.Show(message, "Data Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
private void button1_Click(object sender, EventArgs e)
{
AddModifyStudentRecords AddStudent = new AddModifyStudentRecords(StudentTrackerDataset);
AddStudent.ShowDialog();
}
private void button2_Click(object sender, EventArgs e)
{
object id = dataGridView1.CurrentRow.Cells["StudentID"].Value;
DataRow StudentRow = StudentTrackerDataset.Tables["Student"].Rows.Find(id);
AddModifyStudentRecords modifyStudent = new AddModifyStudentRecords(StudentTrackerDataset, StudentRow);
modifyStudent.ShowDialog();
}
private void button3_Click(object sender, EventArgs e)
{
DialogResult result = MessageBox.Show("Are you sure", "Delete Current Row", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (result == DialogResult.Yes)
{
object id = dataGridView1.CurrentRow.Cells["StudentID"].Value;
DataRow currentRow = StudentTrackerDataset.Tables["Student"].Rows.Find(id);
currentRow.Delete();
}
}
private void button4_Click(object sender, EventArgs e)
{
if (!StudentTrackerDataset.HasChanges())
{
MessageBox.Show("There are no Change to Save ", "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
else
{
try
{
DataSet changesDateSet = StudentTrackerDataset.GetChanges();
ProjectOfSchool.DataAccessLayer.DAC.SaveData(ref changesDateSet);
StudentTrackerDataset.Merge(DAC.GetData());
MessageBox.Show("Data Save Successfully.", "Save Changes");
}
catch (SqlException ex)
{
MessageBox.Show("Data Not Saved:" + ex.Message, "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
}
private void button5_Click(object sender, EventArgs e)
{
if (!StudentTrackerDataset.HasChanges())
{
MessageBox.Show("There are no Changes to Save.", "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
else
{
DialogResult result = MessageBox .Show ("Are you Sure?","Reject Changes", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (result == DialogResult.Yes )
{
StudentTrackerDataset.RejectChanges();
}
}
}
当我终止程序并重新执行程序时，我看到StudntID = 1也保存到ID = 1的数据库
或当我删除StudentID = 1并按保存更改后按保存更改当我也终止程序并重新退出程序，之后我输入StudentID = 1然后没有错误发生
其他没有终止的方法是删除记录StudentID1但是当你添加学生记录而不是添加StudentID = 1但是在这种情况下添加除1以外的StudentID也不会发生错误。亲爱的Sherik我已经解决了我的其他错误，但我仍然有错误，这是我的Tittle所以请回答我这个错误我也重新编辑我的代码所以请重播我谢谢
我的数据库中有记录，其数据类型为
StudentID = INT，
姓= VARCHAR，则
名字= VARCHAR，则
性别= VARCHAR，则
GPA =浮动，
MyImage = Vabinary（MAX）
或者可能是Datarow无法删除记录或更新记录。我不知道请告诉我，谢谢回复我，我等你的回复。
答案 0 :(得分：0)
错误消息似乎表明您正在点击主键约束。 我建议您先停止允许用户输入学生ID字段。让它在您使用的任何数据库中生成为自动增量键。在Access中，它被称为自动编号。
完成后，重新测试并发布结果。