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  Graph color list from dB table
Posted by Bill on Jun-05-2020 13:05
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How do I call the color code (0xFF0000) store in SQL dB table and paste it in my Graph table like this.

string mycolor = "0xFF0000";  //I stored this value as NVARCHAR(10) in my SQL table.
BarLayer layer = c.addBarLayer2(Chart.Side, 0);
layer.addDataSet(OUT, "+mycolor+", "ACTUAL VOL (KU)");

With this, there was an error. not int format.
What should be the syntax here?
Thanks in advance - Bill

  Re: Graph color list from dB table
Posted by Peter Kwan on Jun-05-2020 13:59
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Hi Bill,

The color is a 32-bit integer. 0xFF0000 is a 32-bit integer in the C# language, so it can be used. "0xFF0000" is not an integer in the C# language. It is a text string. As C# is a strongly type language, it would not allow the code to compile.

To solve the problem, you can simply convert the text string to an integer using the C# function Convert.Int32.

int myColor = Convert.ToInt32("0xFF0000", 16);

See:

https://docs.microsoft.com/en-us/dotnet/api/system.convert.toint32?view=netframework-4.0#System_Convert_ToInt32_System_String_System_Int32_

If you can change the database schema, a better method is to store the color as an 32-bit integer in the first place and not as a text string. In this way, no conversion is necessary and the color is always valid. If you store as NVARCHAR, there is always a risk that the text is invalid. For example, if the color is entered by a user, he may enter "0xXYZ19845" and this may get stored in the database. This would cause the C# Convert.ToInt32 to throw an exception at runtime and you may need extra code to validate and handle all these situations.

Regards
Peter Kwan