C# Discussion Boards - CodeProject

22-May-06 12:30

I have some grid controls on a form that are using data adaptors to fill the grid directly from the SQL Server data base. I have added an even handler on exit of the form to commit changes but the changes are not getting written back to the data base.

Here is my code -

this.speciesTableAdapter.Fill(this.markingDBDataSet3.Species);

private void MasterData_FormClosing(object sender, FormClosingEventArgs e)
{
SpeciesGrid.CommitEdit(DataGridViewDataErrorContexts.Commit);
SpeciesGrid.Update();
}

I must be missing something or I am totally on the wrong track. Any ideas?

-- modified at 18:42 Monday 22nd May, 2006

Sean8922-May-06 13:07

Sean89

22-May-06 13:07

Ok. To update the database based on changes you have made in the datagrid you must be calling the DataAdapter.Update() method. This takes two arguments: Your datatable/dataset (this will be the datasource of your grid), and (if you hand it a dataset) the name of the table.

Ex.
dAdapter.Update(somedataset, "Table");
or
dAdapter.Update(sometable);

But you do need to specify an insert command in order for this to work. If a standard insert query is fine, you can use the command builder class. So, if you are using OleDb it would be like this:

OleDbCommandBuilder cmdBuild = new OleDbCommandBuilder(dAdapter);<br />
dAdapter.Update(somedataset, "Table");

Hope that helps! Poke tongue | ;-P

tjschilling23-May-06 4:45

23-May-06 4:45

I am using a SqlDatatAdaptor and when I try this solution, it builds without any errors but when the update is executed, I get the following exception error -

Update requires a valid UpdateCommand when passed DataRow collection with modified rows.

This is my code -

SqlDataAdapter dAdapter = new System.Data.SqlClient.SqlDataAdapter();

dAdapter.Update(markingDBDataSet3, "Species");

Sean8923-May-06 9:15

Sean89

23-May-06 9:15

You need to include the SqlCommandBuilder to make your update command for you:

SqlDataAdapter dAdapter = new SqlDataAdapter();

SqlCommandBuilder cmdBuild = new SqlCommandBuilder(dAdapter);  // add this

dAdapter.Update(markingDBDataSet3, "Species");

Without this, the update will not work.

tjschilling23-May-06 10:13

23-May-06 10:13

I added the code as sugested -

SqlDataAdapter dAdapter = new SqlDataAdapter();
SqlCommandBuilder cmdBuild = new SqlCommandBuilder(dAdapter);
dAdapter.Update(markingDBDataSet3,"Species");

I am now getting a different error.

Error -
The DataAdapter.SelectCommand property needs to be initialized.

Resolved

tjschilling23-May-06 12:10

DataGridViewCheckBoxColumn values

23-May-06 12:10

Sean, you got me pointed in the right direction. I worked with one of the more experienced Windows developers here and we managed to cobble together the following which seems to be working. Evidently it needed a reference to the table adaptor and needed a select command added to the data adaptor.

Here is the code -

SqlDataAdapter dAdapter = new SqlDataAdapter();
SqlCommandBuilder cmdBuild = new SqlCommandBuilder(dAdapter);
dAdapter.SelectCommand = new SqlCommand("select * from Species");
dAdapter.SelectCommand.Connection = speciesTableAdapter.Connection;
dAdapter.Update(markingDBDataSet3,"Species");

Thank you very much for your help! Smile | :)

Re: Resolved

Sean8924-May-06 10:11

Sean89

24-May-06 10:11

Ohh sorry I would have told you to put a select command in when initializing the data adapter but I thought you had just left it out so you wouldnt take up to much room in your post Wink | ;)

Good to see you got it workin' Wink | ;)

Elvia Gonzalez22-May-06 12:21

Elvia Gonzalez

22-May-06 12:21

Hi there,

I'm using DataGridViewCheckBoxColumn, when a check box is unchecked sometimes I get the value {} (it's not a string value) instead of false. I want to get the value false or true.

Does anybody know why do I get the value {} and how can identify this value programatically?

Thanks in advance,

Elvia

PS: Windows application in Microsoft Visual C# 2005

datagridview

kjosh22-May-06 10:13

kjosh

22-May-06 10:13

Hi,
Iam using datagridview,How to add a new row to the datagrid view?
In insert button i wrote this code,
dataGridView1.Rows.Add(3);
when i run this code,it is giving the following exception
exception: rows cannot be programatically to the datagridview's collection when control is databound

In save button i wrote like this,

private void button1_Click(object sender, EventArgs e)

{da.Update(ds,"emp");

}

It is giving the following exception:

Update requires a valid InsertCommand when passed DataRow collection with new rows.

Please help me.
Thanks In Advance

Re: datagridview

led mike22-May-06 10:29

Using expressions with resource only assembly

22-May-06 10:29

You need an introduction. Try this article[^]

"What classes are you using ? You shouldn't call stuff if you have no idea what it does"
Christian Graus in the C# forum

led mike

koenjordens22-May-06 9:36

koenjordens

22-May-06 9:36

Is there a way to access the resources in referenced assemblies ?
e.g. <asp:Label ID="Label2" runat="server" Text="<%$ Resources:MyResources, MyText %>"></asp:Label>
but with a MyResources assembly that was referenced instead of resources in the global_resources folder

Catch WebException on async download

Erikerikerikerikerassa22-May-06 8:46

Erikerikerikerikerassa

22-May-06 8:46

If i have this codesnippet and the specified url doesn't exist.
How do i catch the webexception?

WebClient laddaner = new WebClient();
laddaner.DownloadStringCompleted += new DownloadStringCompletedEventHandler(laddaner_DownloadStringCompleted);
laddaner.DownloadStringAsync(new Uri("http://thisurldoesnotexist.com"));

Right now i get a TargetInvokationException thrown at Application.Run(new Form1()); in Program.cs (the program is a simple Form-app)

This doesn't work:

WebClient laddaner = new WebClient();
laddaner.DownloadStringCompleted += new DownloadStringCompletedEventHandler(laddaner_DownloadStringCompleted);

try
{
   laddaner.DownloadStringAsync(new Uri("http://thisurldoesnotexist.com"));
}
catch(WebException)
{
   MessageBox.Show("Error!");
}

Re: Catch WebException on async download

led mike22-May-06 9:27

Re: Catch WebException on async download

22-May-06 9:27

try using WebClient.OpenReadAsync() and check the OpenReadCompletedEventArgs.Error in the handler for OpenReadCompleted event.

"What classes are you using ? You shouldn't call stuff if you have no idea what it does"
Christian Graus in the C# forum

led mike

Erikerikerikerikerassa22-May-06 10:00

Erikerikerikerikerassa

22-May-06 10:00

Works perfekt, thanks alot Smile | :)

void blabla()
{
  WebClient laddaner = new WebClient();
  laddaner.OpenReadCompleted += new OpenReadCompletedEventHandler(laddaner_OpenReadCompleted);
  laddaner.OpenReadAsync(new Uri("http://adress.com"));
}

void laddaner_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
  if (e.Error.Message == null)
  {
    StreamReader sr = new StreamReader(e.Result);
    string s = sr.ReadToEnd();
  }
  else
    MessageBox.Show(e.Error.Message);
}

VS2005 Cross Thread

donkaiser22-May-06 8:06

22-May-06 8:06

I have 2 forms.
disable some buttons;
form1 call some bool function on form2(via a delegate).
this function will print some stuff on a textbox in form1 via a cross thread handler.
if the function return true then enable the buttons.
simple enough. but vs2005 give me this error:
"Cross-thread operation not valid: Control 'button1' accessed from a thread other than the thread it was created on."

Does anyone knows what is going here? And how i can solve it?

Donkaiser

Re: VS2005 Cross Thread

donkaiser22-May-06 8:07

Re: VS2005 Cross Thread [modified]

22-May-06 8:07

oh one more thing my program is in C# so i guess if i post it in this forum it may help.

Donkaiser

led mike22-May-06 8:21

Re: VS2005 Cross Thread [modified]

22-May-06 8:21

see: System.Windows.Forms.Control.Invoke() method and BeginInvoke

"What classes are you using ? You shouldn't call stuff if you have no idea what it does"
Christian Graus in the C# forum

led mike

-- modified at 14:22 Monday 22nd May, 2006

Also see the forum thread about 5 positions below this one on the same subject.

donkaiser22-May-06 8:28

Re: VS2005 Cross Thread [modified]

22-May-06 8:28

well i just after wanna do like
button1.enable = false;
if(somedelegate funcOnform2())
{
button1.enable = true;
}

and the IDE gave me the error at button1.enable = true;

Donkaiser

led mike22-May-06 9:06

22-May-06 9:06

donkaiser wrote:
well i just after wanna do like

Whatever. good luck

"What classes are you using ? You shouldn't call stuff if you have no idea what it does"
Christian Graus in the C# forum

led mike

Re: VS2005 Cross Thread

Judah Gabriel Himango22-May-06 9:25

Judah Gabriel Himango

22-May-06 9:25

You can only access Form1 on the thread it was created on. You can only access Form2 on the thread it was created on. And so on. This is the reason you're getting an error.

In order to solve this, you need to actually perform the work on the correct thread. To do this, you can use form.Invoke, which will bring the work onto the correct thread for that form.

// Inside form2, on a thread other than the thread that created Form1.
// Pretend we want to change the Enabled property to true.

ThreadStart functionThatChangesEnabledState = delegate()
{
    form1.Enabled = true;
};

form1.Invoke(functionThatChangesEnabledState);

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Islamic Domination: Coming to a Jewish state near you!
The apostle Paul, modernly speaking: Epistles of Paul

Judah Himango

Re: VS2005 Cross Thread

donkaiser23-May-06 6:59