csharp DataGridView-DataTable.GetChanges返回null. [英] csharp DataGridView - DataTable.GetChanges returns null.
问题描述
DataTable.GetChanges有时即使返回更改也返回null.
1.在第一行(C，1)中编辑一个单元格，应用更改并将其成功保存到DB.光标返回时移动到单元格(C，2).
这比我想象的更奇怪，因为DataTable changeTable = DataTableTopLevel.GetChanges();返回null，但仍保存
2.在第二行(C，2)中编辑一个单元格，返回键上的值将更改回去.光标也不会移至(C，3)，但是光标移至(A，3).
DataTable changeTable = DataTableTopLevel.GetChanges();返回非null，但不保存.
3.在第三行(C，3)中编辑一个单元格，应用更改并将其成功保存到DB.光标返回时移动到单元格(C，4).
DataTable.GetChanges returns null sometimes even though changes have been made.
1.Edit a cell in first row (C,1), change is applied and saves successfully to DB. Cursor moves to cell (C,2) on return.
This is more odd than I thought as DataTable changeTable = DataTableTopLevel.GetChanges(); returns null, but it still saves
2.Edit a cell in second row (C,2), value changes back on return key. Also cursor does not move to (C,3) BUT moves to (A,3).
DataTable changeTable = DataTableTopLevel.GetChanges(); returns non null, but is not saved.
3.Edit a cell in third row (C,3), change is applied and saves successfully to DB. Cursor moves to cell (C,4) on return.
public partial class MeServerMainForm : Form
{
string connServer;
string qryServerTopLevel;
string qryServerBottomLevel;
SqlDataAdapter SqlAdapterTopLevel;
SqlDataAdapter SqlAdapterBottomLevel;
SqlCommandBuilder SqlCommandBuilderTopLevel;
SqlCommandBuilder SqlCommandBuilderBottomLevel;
DataTable DataTableTopLevel;
DataTable DataTableBottomLevel;
BindingSource BindingSourceTopLevel;
BindingSource BindingSourceBottomLevel;
bool TopLevelCellValueChanged;
public MeServerMainForm()
{
InitializeComponent();
InitData();
TopLevelCellValueChanged = false;
}
public void InitData()
{
//create the connection string
connServer = "Data Source=192.168.0.11;Initial Catalog=Phil;User Id=Philip;Password=Philip;";
// TOP LEVEL
//create the database query
qryServerTopLevel = @"SELECT
MeID
,MeTypeID
,MeTitle
,CreatedDateTime
,ReadOnly
,ParentMeID
,Question
,Answer
,MeScore
,MeLastTestDate
FROM MyMees
WHERE ParentMeID = 0 ";
//create an OleDbDataAdapter to execute the query
SqlAdapterTopLevel = new SqlDataAdapter(qryServerTopLevel, connServer);
//create a command builder
SqlCommandBuilderTopLevel = new SqlCommandBuilder(SqlAdapterTopLevel);
//create a DataTable to hold the query results
DataTableTopLevel = new DataTable();
//fill the DataTable
SqlAdapterTopLevel.Fill(DataTableTopLevel);
//BindingSource to sync DataTable and DataGridView
BindingSourceTopLevel = new BindingSource();
//set the BindingSource DataSource
BindingSourceTopLevel.DataSource = DataTableTopLevel;
//set the DataGridView DataSource
DataGridViewTopLevel.DataSource = BindingSourceTopLevel;
// Bottom LEVEL
//create the database query
qryServerBottomLevel = @"SELECT
MeID
,MeTypeID
,MeTitle
,CreatedDateTime
,ReadOnly
,ParentMeID
,Question
,Answer
,MeScore
,MeLastTestDate
FROM MyMees
WHERE ParentMeID = 2 ";
//create an OleDbDataAdapter to execute the query
SqlAdapterBottomLevel = new SqlDataAdapter(qryServerBottomLevel, connServer);
//create a command builder
SqlCommandBuilderBottomLevel = new SqlCommandBuilder(SqlAdapterBottomLevel);
//create a DataTable to hold the query results
DataTableBottomLevel = new DataTable();
//fill the DataTable
SqlAdapterBottomLevel.Fill(DataTableBottomLevel);
//BindingSource to sync DataTable and DataGridView
BindingSourceBottomLevel = new BindingSource();
//set the BindingSource DataSource
BindingSourceBottomLevel.DataSource = DataTableBottomLevel;
//set the DataGridView DataSource
DataGridViewBottomLevel.DataSource = BindingSourceBottomLevel;
DataTableTopLevel.AcceptChanges();
}
private void loadMeTreeToolStripMenuItem_Click(object sender, EventArgs e)
{
}
private void DataGridViewTopLevel_RowLeave(object sender, DataGridViewCellEventArgs e)
{
DataTable changeTable = DataTableTopLevel.GetChanges();
if (changeTable != null)
{
SqlAdapterTopLevel.Update(DataTableTopLevel);
DataTableTopLevel.AcceptChanges();
DataTableTopLevel.Clear();
SqlAdapterTopLevel.Fill(DataTableTopLevel);
TopLevelCellValueChanged = false;
}
}
有什么想法吗?
谢谢
Phil
Any ideas?
Thanks
Phil
推荐答案
为什么不使用DataGridViewCellEventArgs?
http://msdn.microsoft.com/en-us/library/system. windows.forms.datagridviewcelleventargs.aspx [ ^ ]
看一下这些话(我会解释一下):
http://msdn.microsoft.com/en-us/library/5dxfaha8.aspx [ ^ ]
祝你好运！
Why not use the DataGridViewCellEventArgs?
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridviewcelleventargs.aspx[^]
Have a look at the remarks (that will explain I think):
http://msdn.microsoft.com/en-us/library/5dxfaha8.aspx[^]
Good luck!
我正在使用DataGridView.RowLeave，我应该使用DataGridView.RowValidated.我相信这是因为可以在RowValidated发生之前触发行离开事件.发生这种情况时，DataGridView.GetChanged()返回null.
例子
I was using DataGridView.RowLeave, I should have used DataGridView.RowValidated. I believe this is because the row leave event can be fired before RowValidated has occurred. When this happens, DataGridView.GetChanged() returns null.
example
private void DataGridViewTopLevel_RowValidated(object sender, DataGridViewCellEventArgs e)
{
DataTable changeTable = DataTableTopLevel.GetChanges();
if (changeTable != null)
{
SqlAdapterTopLevel.Update(DataTableTopLevel);
}
}
谢谢您对Nijboer的帮助，我现在将DataGridViewCellEventArgs用于其他用途.
Thanks for you help E.F. Nijboer, I am now using the DataGridViewCellEventArgs for other uses.
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