删除组合框中的所选项目 [英] Remove selected item in combobox
问题描述
我要删除我的组合框中的所选项
I want to remove a selected item in my combobox
我在表单加载时在这里有一个代码，我从数据库填充combobox上的列表项。
I have here a code upon form load, I am filling list items on combobox from database.
private void LoadComboField()
{
//string test = "<ROOT><DATA FieldGroup=\"PAYMENT_VIEW4\" FieldDescription=\"PNAME\" Output=\"1\" Filter=\"1\" FieldName=\"PATIENTNAME\" DataType=\"STRING\"/><DATA FieldGroup=\"PAYMENT_VIEW4\" FieldDescription=\"MEMID\" Output=\"1\" Filter=\"1\" FieldName=\"MEMBERID\" DataType=\"STRING\"/></ROOT>";
ReadXMLData(XMLDOC, dsCombo);
// ReadXMLData(test, dsCombo);
dt = dsCombo.Tables[0];
DataView dv1 = new DataView(dsCombo.Tables[0]);
this.cmbField.Items.Clear();
this.cmbField.DataSource = dv1;
this.cmbField.DisplayMember = "FieldDescription";
this.cmbField.ValueMember = "FieldName";
}
然后我在SelectedValueChanged上有这个代码
Then I have this code on SelectedValueChanged
private void cmbField_SelectedValueChanged(object sender, EventArgs e)
{
DataGridViewRow GridRowLoc = this.dgvFilter.CurrentRow;
AddGrid(iRowIdx);
int iRowCount = this.dgvFilter.RowCount - 1;
//this.dgvFilter.CurrentRow.IsNewRow
//if (GridRowLoc.IsNewRow) continue;
// MessageBox.Show(this.dgvFilter.RowCount.ToString());
if (this.cmbField.Text != "System.Data.DataRowView")
{
this.dgvFilter.Rows[iRowIdx].Cells["ColumnFieldName"].Value = this.cmbField.Text;
this.dgvFilter.Rows[iRowIdx].Cells["FieldName"].Value = this.cmbField.SelectedValue;
if (iRowCount <= iRowIdx)
{
DataRow drow = dttable.NewRow();
drow["ColumnNames"] = this.cmbField.Text;
drow["FieldName"]= this.cmbField.SelectedValue;
drow["Alias"]=string.Empty;
drow["DataType"]=string.Empty;
drow["Outputs"]=false;
drow["SortType"]=string.Empty;
drow["SortOrder"]=string.Empty;
drow["GroupBy"]=string.Empty;
drow["Filter"]=string.Empty;
drow["Or1"]=string.Empty;
drow["Or2"]=string.Empty;
drow["Or3"]=string.Empty;
drow["Or4"]=string.Empty;
drow["Or5"]=string.Empty;
drow["Or6"]=string.Empty;
drow["Or7"]=string.Empty;
drow["Or8"]=string.Empty;
drow["Or9"]=string.Empty;
drow["Or10"]=string.Empty;
dttable.Rows.Add(drow);
}
else
{
int irow = 0;
foreach (DataRow dr in dttable.Rows)
{
if (irow == iRowIdx)
{
dr["ColumnNames"] = this.cmbField.Text;
dr["FieldName"] = this.cmbField.SelectedValue;
}
irow++;
}
}
CheckAlias(iRowIdx, this.cmbField.Text, dgvFilter);
checkcellvalue(this.cmbField.Text, iRowIdx);
CheckSorting();
if (bGroupBySelected == true)
{
this.dgvFilter.Rows[iRowIdx].Cells["GroupBy"].Value = "Group By";
}
this.dgvFilter.DataSource = dttable;
dsFilter.AcceptChanges();
this.cmbField.Visible = false;
}
// checkcellvalue(this.cmbField.Text, iRowIdx);
//MessageBox.Show(arr_Filter[0]);
CheckoutputEnable();
}
我在SelectedIndexChanged中有此代码
I have this code in SelectedIndexChanged
try
{
DataTable dt1 = new DataTable();
DataRowView oDataRowView = cmbField.SelectedItem as DataRowView;
string sValue = string.Empty;
if (oDataRowView != null)
{
sValue = oDataRowView.Row["FieldDescription"] as string;
}
//int count = dttable.Rows.Count - 1;
ComboBox comboBox = (ComboBox)sender;
// Save the selected employee's name, because we will remove
// the employee's name from the list.
string selectedEmployee = (string)sValue;
int count = 0;
int resultIndex = -1;
// Call the FindStringExact method to find the first
// occurrence in the list.
resultIndex = cmbField.FindStringExact(selectedEmployee);
// Remove the name as it is found, and increment the found count.
// Then call the FindStringExact method again, passing in the
// index of the current found item so the search starts there
// instead of at the beginning of the list.
while (resultIndex != -1)
{
cmbField.Items.RemoveAt(resultIndex);
count += 1;
resultIndex = cmbField.FindStringExact(selectedEmployee,
resultIndex);
}
// Update the text in Textbox1.
txtName.Text = txtName.Text + "\r\n" + selectedEmployee + ": "
+ count;
}
//}
catch (Exception ex)
{
}
但它抛出一个异常，说当设置了datasource属性时，不能修改items集合。我不知道如何解决这个异常错误，我认为这是我唯一的问题，当删除组合框上的项目。
But it throws an exception, say that "items collection cannot be modified when the datasource property is set." I don't know how to fix this exception error, I think that's my only problem when removing an item on the combobox.
请帮助我在这一个。提前感谢！
Please do help me on this one. Thanks in advance!
推荐答案
您无法修改 Items 当它来自/被绑定到一个 DataSource 。您需要修改 DataSource 本身。
You can't modify the Items collection when it comes from / is bound to a DataSource. Instead you need to modify the DataSource itself.
要删除 SelectedItem 从 DataSource 可以尝试：
DataRowView item = cmbField.SelectedItem as DataRowView;
if (item != null) item.Delete();
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