Why can't I do this??

[Siv]

Hi,
This is driving me nuts, I have executed a SQL Stored Procedure that
populates a SQLDataReader (dr) and am reading in some fields that contain
numbers into a Struct that I have defined as follows:

=============== =============== ===========
public struct KPIData
{
public byte Cond;
public Single Min;
public Single Max;
public Single Points;
public byte Band;
}

// I then instantiate an array called CSP with space for 11 items:

KPIData[] CSP;

CSP=new KPIData[10];

// Database stuff executes Stored Procedure and populates the DataReader
// Then eventually I do:

while (dr.Read())
{

CSP[n].Cond = (byte) dr["CondType"];
CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];
CSP[n].Band = (byte) dr["Band"];
n += 1;
z= n % 10;

if (z== 0)
Array.Resize(re f CSP, CSP.Length + 10);

}

=============== =============== ===========
The lines:

CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];

All cause Explicit Type Conversion errors yet the byte ones work as I would
expect??
Can anyone explain to a Newbie why this is a problem, I have tried
substituting Float instead of Single and it still errors just the same???
--
Siv
Martley, Near Worcester, United Kingdom.

[Greg Young [MVP]]

What is the datatype of the item in the row? Most likely it does not support
an explicit conversion to a single.

Cheers,

Greg

"Siv" <dotnet@remove_ me.sivill.com> wrote in message
news:eW******** ******@TK2MSFTN GP03.phx.gbl...

Hi,
This is driving me nuts, I have executed a SQL Stored Procedure that
populates a SQLDataReader (dr) and am reading in some fields that contain
numbers into a Struct that I have defined as follows:

=============== =============== ===========
public struct KPIData
{
public byte Cond;
public Single Min;
public Single Max;
public Single Points;
public byte Band;
}

// I then instantiate an array called CSP with space for 11 items:

KPIData[] CSP;

CSP=new KPIData[10];

// Database stuff executes Stored Procedure and populates the DataReader
// Then eventually I do:

while (dr.Read())
{

CSP[n].Cond = (byte) dr["CondType"];
CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];
CSP[n].Band = (byte) dr["Band"];
n += 1;
z= n % 10;

if (z== 0)
Array.Resize(re f CSP, CSP.Length + 10);

}

=============== =============== ===========
The lines:

CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];

All cause Explicit Type Conversion errors yet the byte ones work as I
would expect??
Can anyone explain to a Newbie why this is a problem, I have tried
substituting Float instead of Single and it still errors just the same???
--
Siv
Martley, Near Worcester, United Kingdom.

[Siv]

It's a "Decimal" in SQL Server.
If I can't use single/float could I use another data type in C# that would
receive the field value. I must admit I thought it was complaining because
the data reader field was classed as an "object"?

--
Siv
Martley, Near Worcester, United Kingdom.
"Greg Young [MVP]" <Dr************ *@hotmail.com> wrote in message
news:eF******** ******@TK2MSFTN GP05.phx.gbl...

What is the datatype of the item in the row? Most likely it does not
support an explicit conversion to a single.

Cheers,

Greg

"Siv" <dotnet@remove_ me.sivill.com> wrote in message
news:eW******** ******@TK2MSFTN GP03.phx.gbl...

Hi,
This is driving me nuts, I have executed a SQL Stored Procedure that
populates a SQLDataReader (dr) and am reading in some fields that contain
numbers into a Struct that I have defined as follows:

=============== =============== ===========
public struct KPIData
{
public byte Cond;
public Single Min;
public Single Max;
public Single Points;
public byte Band;
}

// I then instantiate an array called CSP with space for 11 items:

KPIData[] CSP;

CSP=new KPIData[10];

// Database stuff executes Stored Procedure and populates the DataReader
// Then eventually I do:

while (dr.Read())
{

CSP[n].Cond = (byte) dr["CondType"];
CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];
CSP[n].Band = (byte) dr["Band"];
n += 1;
z= n % 10;

if (z== 0)
Array.Resize(re f CSP, CSP.Length + 10);

}

=============== =============== ===========
The lines:

CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];

All cause Explicit Type Conversion errors yet the byte ones work as I
would expect??
Can anyone explain to a Newbie why this is a problem, I have tried
substituting Float instead of Single and it still errors just the same???
--
Siv
Martley, Near Worcester, United Kingdom.

[Siv]

Greg,

I changed the Singles to Decimals and all is well. I was being confused by
the compiler error messages, it kept saying that dr["csMin"] was type
"object" so it threw me off on the wrong path!
Thankfully you have me back on it again, many thanks.
--
Siv
Martley, Near Worcester, United Kingdom.
"Greg Young [MVP]" <Dr************ *@hotmail.com> wrote in message
news:eF******** ******@TK2MSFTN GP05.phx.gbl...

What is the datatype of the item in the row? Most likely it does not
support an explicit conversion to a single.

Cheers,

Greg

"Siv" <dotnet@remove_ me.sivill.com> wrote in message
news:eW******** ******@TK2MSFTN GP03.phx.gbl...

Hi,
This is driving me nuts, I have executed a SQL Stored Procedure that
populates a SQLDataReader (dr) and am reading in some fields that contain
numbers into a Struct that I have defined as follows:

=============== =============== ===========
public struct KPIData
{
public byte Cond;
public Single Min;
public Single Max;
public Single Points;
public byte Band;
}

// I then instantiate an array called CSP with space for 11 items:

KPIData[] CSP;

CSP=new KPIData[10];

// Database stuff executes Stored Procedure and populates the DataReader
// Then eventually I do:

while (dr.Read())
{

CSP[n].Cond = (byte) dr["CondType"];
CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];
CSP[n].Band = (byte) dr["Band"];
n += 1;
z= n % 10;

if (z== 0)
Array.Resize(re f CSP, CSP.Length + 10);

}

=============== =============== ===========
The lines:

CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];

All cause Explicit Type Conversion errors yet the byte ones work as I
would expect??
Can anyone explain to a Newbie why this is a problem, I have tried
substituting Float instead of Single and it still errors just the same???
--
Siv
Martley, Near Worcester, United Kingdom.

[Michael C]

"Siv" <dotnet@remove_ me.sivill.com> wrote in message
news:eW******** ******@TK2MSFTN GP03.phx.gbl...

// I then instantiate an array called CSP with space for 11 items:

KPIData[] CSP;

CSP=new KPIData[10];
Although I doubt it is the problem this is only 10 items.
CSP[n].Min = (Single) dr["csMin"];
CSP[n].Max = (Single) dr["csMax"];
CSP[n].Points = (Single) dr["Points"];

All cause Explicit Type Conversion errors yet the byte ones work as I
would expect??
Can anyone explain to a Newbie why this is a problem, I have tried
substituting Float instead of Single and it still errors just the same???

Do this:

object x = dr["csMin"];
CSP[n].Min = (Single) x;

When it errors have a look at the value of x. Maybe it is null or string?

Michael

[Hans Kesting]

> It's a "Decimal" in SQL Server.

If I can't use single/float could I use another data type in C# that would
receive the field value. I must admit I thought it was complaining because
the data reader field was classed as an "object"?

--
Siv
Martley, Near Worcester, United Kingdom.

I think that when you have an object which is really a boxed decimal,
you can only cast (unbox) it to a decimal. Only then you can cast
(convert) it to an other type. So this will work:
float f = (float)(decimal )dr["csMin"];

Hans Kesting

[Siv]

Hans,
Wow, I am a VB.NET programmer converting some VB6 stuff to C# and although I
understand C# it isn't my main language, so I am finding this ability to do
type conversions quite an eye opener.

Thanks for your help.
--
Siv
Martley, Near Worcester, United Kingdom.

"Hans Kesting" <ne***********@ spamgourmet.com > wrote in message
news:mn******** *************** @spamgourmet.co m...

It's a "Decimal" in SQL Server.
If I can't use single/float could I use another data type in C# that
would receive the field value. I must admit I thought it was complaining
because the data reader field was classed as an "object"?

--
Siv
Martley, Near Worcester, United Kingdom.

I think that when you have an object which is really a boxed decimal,
you can only cast (unbox) it to a decimal. Only then you can cast
(convert) it to an other type. So this will work:
float f = (float)(decimal )dr["csMin"];

Hans Kesting