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set ComboBox selected item when another combobox changes the selected value c#

class ComboBoxCompany
{
public string Code;
public string Name;
public string Database;
public ComboBoxCompany(string code, string name, string database)
{
Code = code; Name = name; Database = database;
}
public override string ToString()
{
// Generates the text shown in the combo box
return Name;
}
}
class ComboBoxDatabase
{
public string cmpName;
public string dbName;
public ComboBoxDatabase(string cmpname, string dbname)
{
cmpName = cmpname; dbName = dbname;
}
public override string ToString()
{
// Generates the text shown in the combo box
return cmpName + " - " + dbName;
}
}
these are the classes for the 2 comboboxes, so when i select a value of the first one(ComboBoxCompany), i want that the second combobox(ComboBoxDatabase) chooses the "dbName"-Value from the first combobox "Database"-Value
i tried this, but it doesn't
private void cbxBranch_SelectedIndexChanged(object sender, EventArgs e)
{
cbxDatabase.SelectedItem = (cbxCompany.SelectedItem as ComboBoxCompany).Database;
}

by setting
(cbxCompany.SelectedItem as ComboBoxCompany).Database
You try to set the selected item to the database string which does not 'exist' because it seems you added a class as comboboxitem.
You need to set the SelectedItem to the real object. You could search for this by using linq (sample code):
var company = cbxCompany.SelectedItem as ComboBoxCompany;
if(company == null)
return;
var dbItem = _databaseComboBoxItems.FirstOrDefault(x=>x.CompanyName = company.CompanyName && x.Database == company.DatabaseName);
if(dbItem == null)
return;
cbxDatabase.SelectedItem = dbItem;

C# populate a combo box from a method

What I would like to do is to populate a drop down menu from a database.
First of all I plan to use a combo box.
I have created an object that contains the data that I need to take from the database. The object is as follows
namespace RLMD
{
public class FlashCardLevel
{
private int intFCLId;
private String strFCLName;
public FlashCardLevel(int intFCLId, String strFCLName)
{
this.intFCLId = intFCLId;
this.strFCLName = strFCLName;
}
public int IntFCLId
{
get { return intFCLId; }
set { this.intFCLId = value; }
}
public String StrFCLName
{
get { return strFCLName; }
set { this.strFCLName = value; }
}
}
}
What I need to do is to add a list of items from a database, but for ease of use I have simulated given some sample data.
public List<FlashCardLevel> Rifle(List<FlashCardLevel> fcLevel)
{
fcLevel.Add(new FlashCardLevel(1, "Severe"));
fcLevel.Add(new FlashCardLevel(2, "Moderate"));
fcLevel.Add(new FlashCardLevel(3, "Mild"));
fcLevel.Add(new FlashCardLevel(4, "Slight"));
return fcLevel;
}
I'm calling the method here.
List<FlashCardLevel> fcLevel = new List<FlashCardLevel>();
talkToDatabase.Rifle(fcLevel);
this.comboCardLevel.DataSource = fcLevel;
this.comboCardLevel.DisplayMember = "Name";
this.comboCardLevel.ValueMember = "Value";
The combobox is displaying no information.
I would appreciate any help

Updated:
The DisplayMember Property should be referring to FlashCardLevel (class), Property StrFCLName and ValueMember should be pointing to IntFCLId.
List<FlashCardLevel> fcLevel = new List<FlashCardLevel>();
talkToDatabase.Rifle(fcLevel);
this.comboCardLevel.DataSource = listFromDatabase;
this.comboCardLevel.DisplayMember = "StrFCLName";
this.comboCardLevel.ValueMember = "IntFCLId";

The DisplayMember and ValueMember should point to your properties name.
this.comboCardLevel.DisplayMember = "IntFCLId";
this.comboCardLevel.ValueMember = "StrFCLName";

how to make read only property available in my usercontrol

i make user control from 3 text boxes but i don not how to declare read only property to it i tried many things but it do not work here is my code to make the control
i want to make it read only when needed like if i add checkbox i want if checkbox.check=true make my control readonly
public partial class dateIN : UserControl
{
Dates datess = new Dates();
public dateIN()
{
InitializeComponent();
}
private void dateIN_Leave(object sender, EventArgs e)
{
if (txtDay.Text != "" || txtMonth.Text != "" || txtYear.Text != "")
{
if (!datess.IsHijri(txtDay.Text.Trim() + "/" + txtMonth.Text.Trim() + "/" + txtYear.Text.Trim()))
{
txtDay.Focus();
}
}
}
public string Day
{
set { txtDay.Text = value; }
get { return txtDay.Text; }
}
public string Month
{
set { txtMonth.Text = value; }
get { return txtMonth.Text; }
}
public string Year
{
set { txtYear.Text = value; }
get { return txtYear.Text; }
}
need to know how to make read only property available here plz

just remove the set { } part of the property
Example:
public string Day
{
get { return txtDay.Text; }
}

I dont know the correlation of where your "txtDay", "txtMonth", "txtYear" come from, but you could do something like
public partial class dateIN : UserControl
{
...
...
private bool AllowEditing()
{ return SomeCondition when SHOULD be allowed...; }
public string Day
{
// only allow the set to apply the change if the "AllowEditing" condition
// is true, otherwise, ignore the attempt to assign.
set { if( AllowEditing() )
txtDay.Text = value; }
get { return txtDay.Text; }
}
// same concept for month and year too
}

so may you add some flag to your set when it is true then you set a value.
also you can work with textbox property called ReadOnly.

Replacing/changing a blank or null string value in C#

I've got something like this in my property/accessor method of a constructor for my program.
using System;
namespace BusinessTrips
{
public class Expense
{
private string paymentMethod;
public Expense()
{
}
public Expense(string pmtMthd)
{
paymentMethod = pmtMthd;
}
//This is where things get problematic
public string PaymentMethod
{
get
{
return paymentMethod;
}
set
{
if (string.IsNullOrWhiteSpace(" "))
paymentMethod = "~~unspecified~~";
else paymentMethod = value;
}
}
}
}
When a new attribute is entered, for PaymentMethod, which is null or a space, this clearly does not work. Any ideas?

do you perhaps just need to replace string.IsNullOrWhiteSpace(" ") with string.IsNullOrWhiteSpace(value) ?
From your posted code, you need to call:
this.PaymentMethod = pmtMthd;
instead of
paymentMethod = pmtMthd;
The capital p will use your property instead of the string directly. This is why it's a good idea to use this. when accessing class variables. In this case, it's the capital not the this. that makes the difference, but I'd get into the habit of using this.

Jean-Barnard Pellerin's answer is correct.
But here is the full code, which I tested in LinqPad to show that it works.
public class Foo {
private string _paymentMethod = "~~unspecified~~";
public string PaymentMethod
{
get
{
return _paymentMethod;
}
set
{
if (string.IsNullOrWhiteSpace(value))
_paymentMethod = "~~unspecified~~";
else _paymentMethod = value;
}
}
}
With a main of:
void Main()
{
var f = new Foo();
f.PaymentMethod = "";
Console.WriteLine(f.PaymentMethod);
f.PaymentMethod = " ";
Console.WriteLine(f.PaymentMethod);
f.PaymentMethod = "FooBar";
Console.WriteLine(f.PaymentMethod);
}
Output from console:
~~unspecified~~
~~unspecified~~
FooBar

Unable to edit values in a DataGridView (using BindingList)

It seems that, due to an unknown cause, I am now unable to edit anything in my DataGridView. The DGV's ReadOnly property value is false, and all columns except for one all have the ReadOnly property set to false as well.
I'm beginning to think that it may be due to a special value I tried adding to one of my classes, one that I only wanted to be modified within the class, but still read only to the public. I don't think that value is messing with anything else, but none the less, here is the relevant portion of my code:
private void loaderWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
loadingBar.Value = e.ProgressPercentage;
if (e.UserState != null)
{
savefiles.Add((SaveFile)e.UserState);
}
}
Where savefiles is a BindingList, and where SaveFile is my class:
public class SaveFile
{
private string d_directory;
private int d_weirdnumber;
private bool d_isautosave;
private string d_fullname;
private string d_datatype;
private string d_owner;
private bool d_isquicksave;
private string d_title;
private string d_gametime;
public SaveFile() { }
public SaveFile(string directory, int weirdnumber, bool isautosave, string fullname, string datatype, string owner, bool isquicksave, string title)
{
d_directory = directory;
d_weirdnumber = weirdnumber;
d_isautosave = isautosave;
d_fullname = fullname;
d_datatype = datatype;
d_owner = owner;
d_isquicksave = isquicksave;
d_title = title;
}
public string Gametime
{
get { return d_gametime; }
}
public string Datatype
{
get { return d_datatype; }
set { d_datatype = value; }
}
public string Title
{
get { return d_title; }
set { d_title = value; }
}
public bool IsQuickSave
{
get { return d_isquicksave; }
set { d_isquicksave = value; }
}
public bool IsAutoSave
{
get { return d_isautosave; }
set { d_isautosave = value; }
}
public string Directory
{
get { return d_directory; }
set { d_directory = value; }
}
public string FullName
{
get { return d_fullname; }
set
{
d_fullname = value;
string[] split = value.Split(new char[]{'-'});
foreach (string str in split)
{
if (System.Text.RegularExpressions.Regex.IsMatch(str, "^\\d\\d:\\d\\d:\\d\\d$"))
{
d_gametime = str;
}
}
}
}
public int Weirdnumber
{
get { return d_weirdnumber; }
set { d_weirdnumber = value; }
}
public string Owner
{
get { return d_owner; }
set { d_owner = value; }
}
}
Gametime is that special property I mentioned earlier. It doesn't have a set function, but according to this, I should be in the clear, right?
Can anyone then tell me why I may not be able to edit any of the DGV cells?
EDIT: I just found out that not setting AutoGenerateColumns to false allows me to edit again, but I still don't know why.

After several hours, a friend finally took a look at it over Remote Desktop. He wrote a function to force all columns to have a non read-only status, and go figure, it worked. So we looked at the column properties in the editor, and somehow... I don't know why... they were all set to Read only. I swear I checked them 4 times before.
The lesson of this story (I guess): When in doubt, check your settings. When not in doubt, become doubtful. Otherwise, file a bug report to Microsoft :\