Web Forms

Re: can I set a drop down list item to have a value = Null

cluce — Mon, 12 May 2008 15:36:19 GMT

SOLVED!!!

SOlution:

Protected Sub btnAddComp_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddComp.Click

'checks to see if an item is selected

' if not, INSERT NULL

Dim eng As Nullable(Of Integer)

If (ddlEngine.SelectedValue = 0) Then

eng = Nothing

Else

eng = ddlEngine.SelectedValue

End If

Dim mount As Nullable(Of Integer)

If (ddlMount.SelectedValue = 0) Then

mount = Nothing

Else

mount = ddlMount.SelectedValue

End If

Dim inst As Nullable(Of Integer)

If (ddlInstruments.SelectedValue = 0) Then

inst = Nothing

Else

inst = ddlInstruments.SelectedValue

End If

Dim cool As Nullable(Of Integer)

If (ddlCool.SelectedValue = 0) Then

cool = Nothing

Else

cool = ddlCool.SelectedValue

End If

Dim paint As Nullable(Of Integer)

If (ddlPaint.SelectedValue = 0) Then

paint = Nothing

Else

paint = ddlPaint.SelectedValue

End If

Dim safety As Nullable(Of Integer)

If (ddlSafety.SelectedValue = 0) Then

safety = Nothing

Else

safety = ddlSafety.SelectedValue

End If

Dim gen As Nullable(Of Integer)

If (ddlGenerator.SelectedValue = 0) Then

gen = Nothing

Else

gen = ddlGenerator.SelectedValue

End If

Dim elec As Nullable(Of Integer)

If (ddlElectrical.SelectedValue = 0) Then

elec = Nothing

Else

elec = ddlElectrical.SelectedValue

End If

'inserts new match

Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter

componentTypeMatchingAdapter.InsertCompTypeMatch(mount, inst, eng, paint, gen, cool, elec, safety)

GridView1.DataBind()

lblStatus.Text = "A new record was added to the database."

'goes to add a match view

MultiView1.ActiveViewIndex = "1"

End Sub

Re: can I set a drop down list item to have a value = Null

cluce — Mon, 12 May 2008 14:25:07 GMT

I fgured out how to insert a Null value when the dropdown list selected value is = 0

doing this.........but now it wont insert a selected value that is >1 using the IIF condition. It gives me a cast not valid error.

Protected Sub btnAddComp_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddComp.Click
Dim eng As Nullable(Of Integer) = Nothing

'inserts new match
Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter
componentTypeMatchingAdapter.InsertCompTypeMatch(ddlMount.SelectedValue, ddlInstruments.SelectedValue, (IIf(ddlEngine.SelectedValue = 0, eng, ddlEngine.SelectedValue)), ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue)

GridView1.DataBind()
lblStatus.Text = "A new record was added to the database."

'goes to add a match view
MultiView1.ActiveViewIndex = "1"
End Sub

This is strange. It only works one way on the other. The IIF condition does not work right.

This WORKS. but it throws the cast not valid error when the user selects the item with a vlue = 0

componentTypeMatchingAdapter.InsertCompTypeMatch(ddlMount.SelectedValue, ddlInstruments.SelectedValue, ddlEngine.SelectedValue, ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue)

This WORKS..but it only inserts a null value when the user selects the item with a value =0 and it throws a cast not valid error when the user selects anything else.

Dim eng As Nullable(Of Integer) = Nothing

componentTypeMatchingAdapter.InsertCompTypeMatch(ddlMount.SelectedValue, ddlInstruments.SelectedValue, (IIf(ddlEngine.SelectedValue = 0, eng, ddlEngine.SelectedValue)), ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue)

This works but it only inserts a Null value that is not associated with the dropdown list

Dim eng As Nullable(Of Integer) = Nothing

componentTypeMatchingAdapter.InsertCompTypeMatch(ddlMount.SelectedValue, ddlInstruments.SelectedValue, eng , ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue)

can someone tell me why my IIF condition wont work properly. Its like it only works one way or the other but I can't incorporate both

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 21:14:04 GMT

Before run this, why not check the value like

If @MountingID=0 SET @MountingID=NULL

INSERT INTO [componentTypeMatching] ([mountingID], [instrumentsID], [engineID], [paintID], [generatorID], [coolingID], [electricalID], [safetyID])
VALUES (@mountingID, @instrumentsID, @engineID, @paintID, @generatorID, @coolingID, @electricalID, @safetyID)

Re: can I set a drop down list item to have a value = Null

cluce — Fri, 09 May 2008 19:58:05 GMT

I wish I could post the code but InsertTypeCompMatch is the method that was created in the dataset with a table adapter using a query builder. to build this:

and all I do is call the method in my code and fill in those value parameters with whatever control I am using to insert the data with.

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 19:47:26 GMT

What is InsertCompTypeMatch? could you paste code here, so may we can change it insite this function

Re: can I set a drop down list item to have a value = Null

cluce — Fri, 09 May 2008 19:39:53 GMT

I am not sure if the parameter excepts System.Nullable class. I am using a dataset with several Table adapters. This one is unsing the componentTypeTableadapter with an Insert stored procedure as one of the methods. All I do is call this procedure like the following and fill in the parameters.

    Protected Sub btnAddComp_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddComp.Click

        'inserts new match
        Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter
        componentTypeMatchingAdapter.InsertCompTypeMatch(ddlMount.SelectedValue, ddlInstruments.SelectedValue, ddlEngine.SelectedValue, 
        ddlPaint.SelectedValue, ddlGenerator.SelectedValue, 
        ddlCool.SelectedValue, ddlElectrical.SelectedValue,
        ddlSafety.SelectedValue)

        GridView1.DataBind()
        lblStatus.Text = "A new record was added to the database."

        'goes to add a match view
        MultiView1.ActiveViewIndex = "1"
    End Sub

Maybe I might have to hardcode most of this for this to work??

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 19:27:33 GMT

I mean for the parameter in function

In C# need to use

private void Method (int? id)

{

}

is your vb.net has the same sentence?

Re: can I set a drop down list item to have a value = Null

cluce — Fri, 09 May 2008 19:21:06 GMT

I am using SQL server 2005 and the allow Nulls property is set to 'yes' on all my columns. Is there something else I need to check?

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 19:17:07 GMT

Check is that InsertCompTypeMatch support parameter Nothing?

Re: can I set a drop down list item to have a value = Null

cluce — Fri, 09 May 2008 18:00:40 GMT

thanks for the replies. now I am getting a specified cast is not valid error??

   Protected Sub btnAddComp_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddComp.Click

        'inserts new match
        Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter
        componentTypeMatchingAdapter.InsertCompTypeMatch(IIf(ddlMount.SelectedValue = 0, Nothing, ddlMount.SelectedValue), ddlInstruments.SelectedValue, IIf(ddlEngine.SelectedValue = 0, Nothing, ddlEngine.SelectedValue), ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue)
        GridView1.DataBind()
        lblStatus.Text = "New record was added to the database."

        'goes to add a match view
        MultiView1.ActiveViewIndex = "1"
    End Sub

p.s.- my code is vb.net

Re: can I set a drop down list item to have a value = Null

lberan — Fri, 09 May 2008 17:47:14 GMT

the above solution is much better

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 17:41:23 GMT

Try the follow way, it is easy for you.

Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter componentTypeMatchingAdapter.InsertCompTypeMatch(

ddlMount.SelectedValue==0?null:ddlMount.SelectedValue,

ddlInstruments.SelectedValue, ddlEngine.SelectedValue, ddlPaint.SelectedValue, ddlGenerator.SelectedValue, ddlCool.SelectedValue, ddlElectrical.SelectedValue, ddlSafety.SelectedValue) GridView1.DataBind() lblStatus.Text = "New record was added to the database."

Re: can I set a drop down list item to have a value = Null

cluce — Fri, 09 May 2008 17:36:07 GMT

Fistrt off, I am using an object data source to inert my vales. SO I need to figure out a way using this method.

'inserts new match

Dim componentTypeMatchingAdapter As New managementTableAdapters.componentTypeMatchingTableAdapter

GridView1.DataBind()

lblStatus.Text = "New record was added to the database."

Re: can I set a drop down list item to have a value = Null

lberan — Fri, 09 May 2008 17:33:30 GMT

i really hope you wouldn't try the other method since it would be so easy just to insert a null value to the list

Re: can I set a drop down list item to have a value = Null

TonyDong — Fri, 09 May 2008 17:29:13 GMT

/// <summary>

/// Convert empty or null to null

/// </summary>

/// <param name="s">Input value</param>

/// <returns>return null or input value</returns>

public static DateTime? ToDateTime(string s)

{

if (string.IsNullOrEmpty(s)) return null;

if (s.Trim() == string.Empty) return null;

try

{

return (DateTime?)Convert.ToDateTime(s);

}

catch (FormatException ex)

{

throw new FormatException(string.Format("Parameter {0} is not a correct format !", s), ex);

}

/// <summary>

/// Convert empty or null to default value

/// </summary>

/// <param name="s">Input value</param>

/// <param name="defaultValue">default value</param>

/// <returns>return default value or input value</returns>

public static DateTime? ToDateTime(string s, DateTime defaultValue)

{

if (string.IsNullOrEmpty(s)) return defaultValue;

if (s.Trim() == string.Empty) return defaultValue;

return ToDateTime(s);

}