C# 为DatagridView控件提供数据的DataReader-逐行
我有一个处理数据读取的类。请注意,ischanged是我引发的一个事件,用于指示新行的可用性C# 为DatagridView控件提供数据的DataReader-逐行,c#,datagridview,sqldatareader,stack-overflow,C#,Datagridview,Sqldatareader,Stack Overflow,我有一个处理数据读取的类。请注意,ischanged是我引发的一个事件,用于指示新行的可用性 public DataRow FetchNext() { DataRow drow = dt.NewRow(); if (dr.Read() && dr.HasRows) //this will loop through rows unless cancel is clicked { try { for (
public DataRow FetchNext()
{
DataRow drow = dt.NewRow();
if (dr.Read() && dr.HasRows) //this will loop through rows unless cancel is clicked
{
try
{
for (int i = 0; i < listCols.Count; i++)
{
drow[(DataColumn)listCols[i]] = dr[i];
}
dt.ImportRow(drow);
totalRowCount++;
this.isChanged();
return drow;
}
catch (Exception ex)
{
throw;
}
}
else
{
return drow;
}
}
当我点燃一切时,我得到:
System.StackOverflowException was unhandled
_HResult=-2147023895
任何帮助都将不胜感激。好的,下面是答案:
public DataRow FetchNext()
{
DataRow drow = dt.NewRow();
if (dr.Read() && dr.HasRows) //this will loop through rows unless cancel is clicked
{
try
{
for (int i = 0; i < listCols.Count; i++)
{
drow[(DataColumn)listCols[i]] = dr[i];
}
dt.ImportRow(drow);
totalRowCount++;
this.isChanged();
return drow;
}
catch (Exception ex)
{
throw;
}
}
else
{
return drow;
}
}
这确实解决了问题,网格确实是逐行填充的。但是,对于具有数十万行的查询,这将非常耗时。哪行代码会产生异常?FetchNext中的for循环将this dt.rows.Addp.FetchNext;举起手来改变事件?如果是这样,这是一个无止境的循环。这会引发stackoverflowexception吗?如果无止境的循环声明任何资源,它会引发stackoverflowexception或outofmemory异常。如果不是的话,它就挂了。。addRow肯定会占用资源。
public DataRow FetchNext()
{
DataRow drow = dt.NewRow();
if (dr.Read() && dr.HasRows) //this will loop through rows unless cancel is clicked
{
try
{
for (int i = 0; i < listCols.Count; i++)
{
drow[(DataColumn)listCols[i]] = dr[i];
}
dt.ImportRow(drow);
totalRowCount++;
this.isChanged();
return drow;
}
catch (Exception ex)
{
throw;
}
}
else
{
return drow;
}
}
private void buttonGo_Click(object sender, EventArgs e)
{
myrow = p.FetchNext();
this.dt = p.dt.Copy();
bs.DataSource = dt;
dataGridViewMyData.DataSource = bs;
bs.ResetBindings(false);
if (!p.isEnded && !backgroundWorker1.IsBusy )
{
bs.SuspendBinding();
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
bs.SuspendBinding();
if (!p.isEnded)
{
dt.ImportRow(p.FetchNext());
}
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
bs.ResumeBinding();
if (!p.isEnded)
{
backgroundWorker1.RunWorkerAsync();
}
else
{
MessageBox.Show("Done");
}
RefreshData();
}