An Array of a Generic Type

[manishverma]

Hi,
I have been trying to declare an array of generic type, that I want pass as an argument of a function . I have a generic class with two properties;

public class ColumnValuePair<TKey>
{
	public string mstrColumn;
	public TKey mValue;
}

I am trying to take an array of this class as an argument of a function, in some other class - something like this:

public Int32 GetIdentity(argTable, params ColumnValuePair<>[] argKey)
{
	StringBuilder sql = new StringBuilder();
	sql.Append("SELECT " + this.Column + " FROM " + this.Table + " ");
	sql.Append("WHERE ");
	foreach (ColumnValuePair<int, int> key in argKey)
	{
		sql.Append(key.Column + " = ");
		if (key.Value is string)
		{
			sql.Append("'" + key.Value + "'");
		}
		else
		{
			sql.Append(key.Value);
		}
		sql.Append(" AND ");
	}
	if (argKey.Length > 0)
	{
		sql.Remove(sql.Length - 5, 5);
	}
	Int32 id = (Int32)SqlHelper.ExecuteScalar(this.Connection, System.Data.CommandType.Text, sql.ToString());
	return id;
}

Buth this throws error. Could any Guru help?!?

[oohay251]

The first problem is argTable is not assigned a type in your declaration.
I'll assume string for demo purposes.

If you know T at design-time, make the method generic

public Int32 GetIdentity<T>( string argTable, params ColumnValuePair <T>[] argKey)

so,

ColumnValuePair <string> x,y,z;
x = y = z = new ColumnValuePair <string>();
GetIdentity<str ing>("blah",x,y ,x);

If you know T only at run-time or T is going to vary with each method call, you can use the above with the complexities of Reflection, or perhaps just create a base class you can pass your types under:

class CVPBase { }
class ColumnValuePair <T> : CVPBase { }
public Int32 GetIdentity(str ing argTable, params CVPBase[] argKey)
ColumnValuePair <int> x;
ColumnValuePair <string> y,z;
x = new ColumnValuePair <int>();
y = z = new ColumnValuePair <string>();
GetIdentity("bl ah",x,y,x);

[SammyB]

Well, I really cannot make any sense of your code. What are you trying to do? What error are you getting? What line? I'm especially having trouble with "argTable, params ColumnValuePair <>[] argKey" argTable is undeclared, parms is a reserved word, and ColumnValuePair does not have anything in the <>. Please give more details.

Also, this information/book will help, http://www.wrox.com/WileyCDA/Section/id-291522.html