I'm a noob to programming and having a bit of trouble with an assignment. I need to write data from an object that was captured from textboxes into a new row in my Members Table datagridview and then save it to the dataset. (On VS and C#)
AddMember newMember = new AddMember();
newMember.firstName = Firstname.Text;
newMember.lastName = Lastname.Text;
newMember.address = AddLine1.Text;
newMember.phone = Int32.Parse(PHnumber.Text);
newMember.membershipID = comboBox1.SelectedIndex + 1;
newMember.directDebit = paymentoptionID;
newMember.paymentFrequency = paymentFrequencyName;
newMember.extras = checkedListBox1.CheckedIndices.Cast<int> ().ToArray();
I am two Combobox which are populated with a view of a table like following
recieverComboBox.DataSource = myDataSet.Tables[0].DefaultView;
recieverComboBox.DisplayMember = "UserPosition";
recieverComboBox.ValueMember = "ID";
recieverUnReadComboBox.DataSource = myDataSet.Tables[0].DefaultView;
recieverUnReadComboBox.DisplayMember = "UserPosition";
recieverUnReadComboBox.ValueMember = "usr_Id";
when I change the value of each of them, the value of the other one changes automatically. why is that ?
Here are two ways to avoid this issue.
Solution A：
Use BindingSource as the DataSource of ComboBox.
recieverComboBox.DataSource = new BindingSource(myDataSet.Tables[0].DefaultView, null);
recieverComboBox.DisplayMember = "UserPosition";
recieverComboBox.ValueMember = "ID";
recieverUnReadComboBox.DataSource = new BindingSource(myDataSet.Tables[0].DefaultView, null);
recieverUnReadComboBox.DisplayMember = "UserPosition";
recieverUnReadComboBox.ValueMember = "usr_Id";
Solution B:
Call method DataTable.Copy
recieverComboBox.DataSource = myDataSet.Tables[0].Copy();
recieverComboBox.DisplayMember = "UserPosition";
recieverComboBox.ValueMember = "ID";
recieverUnReadComboBox.DataSource = myDataSet.Tables[0].Copy();
recieverUnReadComboBox.DisplayMember = "UserPosition";
recieverUnReadComboBox.ValueMember = "usr_Id";
I think I am overseeing something.
I dynamically generate a few ComboBoxes with this code (I do the same for other controls like TextBox, Label etc)
private ComboBox addControlsComboBox(string Id, string TBName, int point_X, int point_Y, int SizeWidth, DataTable DT)
{
ComboBox combobox = new ComboBox();
combobox.Text = TBName;
combobox.Location = new Point(point_X, point_Y);
combobox.Size = new Size(SizeWidth, 20);
combobox.Name = Id + TBName;
combobox.DataSource = DT;
combobox.DisplayMember = "key";
combobox.ValueMember = "value";
combobox.Enabled = true;
return combobox;
}
When I automatically want to set the selected value, for the controls all the values are set correct except for the ComboBox. Not 1 comboBox is updated but all the ComboBoxes.
I use a nested dictionary object to store all the values that i need to match.
See part of the used update Code
foreach (Control gb in GroupPanel.Controls)
{
foreach (Control childc in gb.Controls)
{
if (DataCollection[GroupNames].ContainsKey(childc.Name))
{
KeyName = childc.Name;
numberLessKeyName = SL.RemoveDigits(childc.Name);
TextValue = DataCollection[GroupNames][KeyName];
switch (NumberLessKeyName)
{
case "Name":
int IntTextValue = Convert.ToInt32(TextValue);
TextValue = IntTextValue.ToString("d2");
break;
}
switch (childc.GetType().ToString())
{
case "System.Windows.Forms.TextBox":
childc.Text = TextValue;
break;
case "System.Windows.Forms.ComboBox":
// Not Working
ComboBox combobox = (ComboBox)childc;
combobox.SelectedValue = TextValue;
//Also not Working
// --> childc.Text = TextValue;
break;
case "System.Windows.Forms.CheckBox":
CheckBox chChildc = (CheckBox)childc;
if (TextValue == "Yes")
{
chChildc.Checked = true;
}
break;
};
}
}
}
What I am doing wrong?
Can somebody help me please?
[EDIT 1]
Thanks to Karol
I added The Following Lines + interface ICloneable and it worked. Many Thanks.
DataTable DT = new DataTable();
DT = DTAttribute;
DataTable DTClone = (DataTable)DT.Clone();
For those searching [C# Object Clone Wars][1] link
[EDIT 2]
A other Idea is to use COPY (works also)
DataTable DT = new DataTable();
DT = DTAttribute;
DataTable DTClone = DT.Copy();
I think You bind all ComboBox same DataTable.
You must have diffrent instance of DataTable for each ComboBox. You can do this in two ways:
- Once again SELECT data from database.
- Use deep copy to make new instance of DataTable.
When the add button is clicked second time, there is supposed to be two lines of data rows in the GridView ( the first row is the first click and the second row is the newly added data). However there is only one data row.
List<DonationReceivedItem> drList = new List<DonationReceivedItem>();
protected void lbnAdd_Click(object sender, EventArgs e)
{
DonationReceivedItem temp = new DonationReceivedItem();
temp.donation = dID;
temp.productVariant = gvSelectVairant.SelectedRow.Cells[1].Text;
temp.productQuantity = tbQuantity.Text;
temp.isDistributed = "0";
drList.Add(temp);
gvNonExpired.DataSource = drList;
gvNonExpired.DataBind();
}
Try changing the following code:
DonationReceivedItem temp = new DonationReceivedItem();
temp.donation = dID;
temp.productVariant = gvSelectVairant.SelectedRow.Cells[1].Text;
temp.productQuantity = tbQuantity.Text;
temp.isDistributed = "0";
drList.Add(temp);
gvNonExpired.DataSource = drList;
gvNonExpired.DataBind();
to:
DonationReceivedItem temp = new DonationReceivedItem();
drList = gvNonExpired.DataSource;
temp.donation = dID;
temp.productVariant = gvSelectVairant.SelectedRow.Cells[1].Text;
temp.productQuantity = tbQuantity.Text;
temp.isDistributed = "0";
drList.Add(temp);
gvNonExpired.DataSource = drList;
gvNonExpired.DataBind();
See if that makes a difference :)
Because you are creating a new list you are wiping the previous data. First instantiate the list with the old data, then add the new data.
Design class which is generated by C# :
//
// usepurposeComboBox
//
this.usepurposeComboBox.DataSource = this.usepurposeBindingSource;
this.usepurposeComboBox.DisplayMember = "Name";
this.usepurposeComboBox.FormattingEnabled = true;
this.usepurposeComboBox.Location = new System.Drawing.Point(277, 53);
this.usepurposeComboBox.Name = "usepurposeComboBox";
this.usepurposeComboBox.Size = new System.Drawing.Size(218, 21);
this.usepurposeComboBox.TabIndex = 4;
this.usepurposeComboBox.ValueMember = "id";
//
// usepurposeBindingSource
//
this.usepurposeBindingSource.DataSource = typeof(mydatabaseEntities.usepurpose);
Then I bound the BindingSource (usepurposeBindingSource) to Entities :
usepurposeBindingSource.DataSource = mydatabaseEntities.usepurposes;
And I can not add a new row to usepurposeComboBox because it's been bound. Is there a workaround ?
The shortest way is to add a new row to your dataTable and then bind your comboBox to it something like this:
Company comps = new Company();
//pupulate dataTable with data
DataTable DT = comps.getCompaniesList();
//create a new row
DataRow DR = DT.NewRow();
DR["c_ID"] = 0;
DR["name"] = "Add new Company";
DR["country"] = "IR";
//add new row to data table
DT.Rows.Add(DR);
//Binding DataTable to cxbxCompany
cxbxCompany.DataSource = DT;
cxbxCompany.DisplayMember = "name";
cxbxCompany.ValueMember = "c_ID";
I'm assuming that you want to add for example a first item sometimes called "Choose One" as if you want to live data you should just see where the data comes from and add more items to that "table".
this.usepurposeBindingSource is an object ... why not adding into it before it binds?
if it's a List<T> this will be fine
this.usepurposeBindingSource.Insert(0, new T() {
Name = "Choose one",
Id = ""
});
Then Bind() it...
Remember to validate as it's a string and will not be the object you want
This is working:
List<MyObject> usepurposeBindingSource { get; set; }
private void FillUpData()
{
// Simulating an External Data
if (usepurposeBindingSource == null || usepurposeBindingSource.Count == 0)
{
this.usepurposeBindingSource = new List<MyObject>();
this.usepurposeBindingSource.Add(new MyObject() { Name = "A", ID = 1 });
this.usepurposeBindingSource.Add(new MyObject() { Name = "B", ID = 2 });
this.usepurposeBindingSource.Add(new MyObject() { Name = "C", ID = 3 });
}
}
private void FillUpCombo()
{
FillUpData();
// what you have from design
// comment out the first line
//this.usepurposeComboBox.DataSource = this.usepurposeBindingSource;
this.usepurposeComboBox.DisplayMember = "Name";
this.usepurposeComboBox.FormattingEnabled = true;
this.usepurposeComboBox.Location = new System.Drawing.Point(277, 53);
this.usepurposeComboBox.Name = "usepurposeComboBox";
this.usepurposeComboBox.Size = new System.Drawing.Size(218, 21);
this.usepurposeComboBox.TabIndex = 4;
this.usepurposeComboBox.ValueMember = "id";
// to do in code:
this.usepurposeBindingSource.Insert(0, new MyObject() { Name = "Choose One", ID = 0 });
// bind the data source
this.usepurposeComboBox.DataSource = this.usepurposeBindingSource;
}
The trick is to comment out the DataSource line and do it in your code, inserting one more element into your object that is from your Model
//this.usepurposeComboBox.DataSource = this.usepurposeBindingSource;
The simplest way to do this, is to wrap your BindingSource with some kind of "ViewModel". The new class will return a "complete" list of items - both those provided from the original binding source, as well as those "additional" items.
You can then bind the new wrapper to your combobox.
I wrote an article about this a while back... It's not my finest work, and it's probably a bit outdated, but it should get you there.
I resolved it on my own. I created a new unbound combobox then bind it to a datatable. Not sure if it's the best way but it works for me. Thanks for all of your suggestions. :)
private void FillCombobox()
{
using (mydatabaseEntities mydatabaseEntities = new mydatabaseEntities())
{
List<usepurpose> usepurposes = mydatabaseEntities.usepurposes.ToList();
DataTable dt = new DataTable();
dt.Columns.Add("id");
dt.Columns.Add("Name");
dt.Rows.Add(-1, "test row");
foreach (usepurpose usepurpose in usepurposes)
{
dt.Rows.Add(usepurpose.id, usepurpose.Name);
}
usepurposeComboBox.ValueMember = dt.Columns[0].ColumnName;
usepurposeComboBox.DisplayMember = dt.Columns[1].ColumnName;
usepurposeComboBox.DataSource = dt;
}
}
Check out this link: http://forums.asp.net/t/1695728.aspx/1?
In asp you can add this to insert an empty line:
<asp:DropDownList ID="CustomerDropDownList" runat="server"
DataSourceID="CustomerEntityDataSource" DataTextField="CustomerId"
DataValueField="CustomerId" AppendDataBoundItems="true">
<asp:ListItem Text="Select All Customers" Value="" />
</asp:DropDownList>
Or in code behind:
DropDownList1.AppendDataBoundItems = true;
DropDownList1.Items.Add(new ListItem("Select All Customers", "-1"));