Convert SQL data type to C# data type

fnGetCSharpTypeNameFromSQLTypeName.sql

ALTER FUNCTION [dbo].[fnGetCSharpTypeNameFromSQLTypeName]
(
    @SQLTypeName NVARCHAR(64)
    , @IsNullable BIT
)
RETURNS NVARCHAR(64)
AS
-- TEST: SELECT dbo.fnGetCSharpTypeNameFromSQLTypeName('MONEY', 1)
BEGIN
    DECLARE @Result NVARCHAR(64)

    SET @Result = CASE @SQLTypeName
        WHEN 'VARCHAR' THEN 'string'
        WHEN 'NVARCHAR' THEN 'string'
        WHEN 'CHAR' THEN 'string'
        WHEN 'NCHAR' THEN 'string'
        WHEN 'INT' THEN 'int'
        WHEN 'MONEY' THEN 'decimal'
        WHEN 'NUMERIC' THEN 'decimal'
        WHEN 'BIT' THEN 'bool'
        WHEN 'IMAGE' THEN 'byte[]'
        WHEN 'DATETIME' THEN 'DateTime'
        WHEN 'SMALLDATETIME' THEN 'DateTime'
        ELSE @SQLTypeName + ' // <-- can not convert'
        END

    IF @Result <> 'string' AND @IsNullable = 1
    BEGIN
        SET @Result = @Result + '?'
    END

    RETURN @Result
END