Hi how can I ignore null values in a reader c# in my statement =>
LegalDesc = reader["legal1"].ToString() + ' ' +
reader["legal2"].ToString() + ' ' +
reader["legal3"].ToString();
Scenario: if legal2 is a null value the resulting string would be
legalDesc = legal1 + ' ' + legal3
How could apply iif used in VB?
You could use a collection and String.Join:
List<string> legals = new List<string>();
if(!reader.IsDbNull(reader.GetOrdinal("legal1")))
legals.Add(reader["legal1"].ToString());
if(!reader.IsDbNull(reader.GetOrdinal("legal2")))
legals.Add(reader["legal2"].ToString());
if(!reader.IsDbNull(reader.GetOrdinal("legal3")))
legals.Add(reader["legal3"].ToString());
LegalDesc = string.Join(" ", legals);
Of course you could also make the code more elegant by using a custom extension method:
public static string SafeGetString(this SqlDataReader reader, int colIndex)
{
if(!reader.IsDBNull(colIndex))
return reader.GetString(colIndex);
else
return string.Empty;
}
Now you can use:
string[] legals = { reader.SafeGetString(0), reader.SafeGetString(1), reader.SafeGetString(2) };
LegalDesc = string.Join(" ", legals.Where(s => !string.IsNullOrEmpty(s)));
This presumes that it's actually a string column and the column ordinal positions are from 0 to 2. If that's not the case use above shown reader.GetOrdinal approach to detect them.
reader.IsDbNull takes an int for the ordinal position of the column(so the index).Using a simple extension method:
public static string ValueOrEmpty(this object source)
{
return source == null ? string.Empty : source.ToString();
}
var values = new[] { reader["legal1"],reader["legal2"],reader["legal3"] };
LegalDesc = string.Join(" ",
values.Select(x => x.ValueOrEmpty())
.Where(x => x != string.Empty));
First
Do Not do string concatenation like that, every time you concatenate, it creates a new instance of string because string is Immutable. There is a C# class that handles appends and it's StringBuilder
So try implementing it like this
StringBuilder builder = new StringBuilder();
builder.Append(reader["legal1"])
.Append(" ")
.Append(reader["legal2"])
.Append(" ")
.Append(reader["legal3"]);
Console.WriteLine(builder.ToString());
Console.ReadKey();
This way, you don't even need to check if it's null.
Hi I just to want rephrase my problem...
how can view a value to a LegalDesc = reader["legal1"].ToString() if legal1 is null?
I am viewing my result in a grid and so the grid shows NULL in the cell. The result should be a blank space instead of NULL.... in VB net I could use the IIf function if null then blank space...
reader["legal2"] ?? " "?reader.IsDbNull?