Re: Passing parameters between form classes - C#

From: Johnny (Johnny_at_discussions.microsoft.com)
Date: 02/08/05 

Date: Mon, 7 Feb 2005 20:09:03 -0800

Antti,

Thank you so much for the suggestion. It worked wonderfully!!!!!
I really appreciate this. I can accomplish what I've been trying to
accomplish.

Thanks,
Johnny

"Antti Keskinen" wrote:

> Hi !
>
> I've solved the case, but this approach has it's limits. First of, it does
> NOT use references. Second, it requires that while the lookup form is
> visible, the user cannot do anything else with the first form. Thirdly, it's
> not very object-oriented.
>
> In the fclsLookup class, make sure you have the following variables:
>
> private System.String m_strSource = String.Empty; // Zip Code passed by the
> first form
> public System.String m_strDestination = String.Empty; // Returns the
> results of the lookup
>
> Change fclsLookup's constructor to this:
>
> public fclsLookup(string SourceZipCode)
> {
> InitializeComponent();
>
> m_strSource = SourceZipCode; // Get the source zip code
>
> /* Rest of this function's code goes here as normal */
> }
>
> In the click handler, do this:
>
> protected void dataGrid1_MouseDown(object sender,
> System.Windows.Forms.MouseEventArgs e)
> {
> // Hit testing
> int x = dataGrid1.HitTest(e.X, e.Y).Row;
>
> // This is the value passed back to the first form
> m_strDestination = dataGrid1[x,0].ToString();
> }
>
> In the first form, where you create and show the lookup form, make sure it
> looks something like this:
> Also, note the order in which the methods are called. This is very
> important.
>
> private void ShowLookup_Click( object sender, System.EventArgs e )
> {
> // Launch the second form (sourceZip is a control which takes the zip
> code)
> fclsLookup Form2 = new fclsLookup( sourceZip.Text );
>
> // Display a modal version of the second form. Execution of this
> function stops here until the lookup form
> // is closed.
> Form2.ShowDialog();
>
> // After the form has been closed, execution continues.
> // When we are here, the click handler in the second form has updated
> the
> // internal value m_strDestination, so we can copy it out
> System.String strReturnValue = objForm2.m_strDestination;
>
> // Use strReturnValue to display the lookup result information.
> }
>
> This is the only approach I could fathom. It seems that the idea of
> 'reference variables' that exists in C++ is a completely unknown feature in
> C#. In C#, you can only have reference variables that live inside a method.
> Reference variables inside a class are an unknown concept altogether. This
> is clearly a limitation of the language, and a one more reason to stick to
> C++ or C++/CLI, when it's finished.
>
> -Antti Keskinen
>
>
> "Johnny" <Johnny@discussions.microsoft.com> wrote in message
> news:EE7EEB70-8EA2-47EF-80A3-C8D714D60C1E@microsoft.com...
> > Antti,
> >
> > I really appreciate the feedback. I should have stated the fact that I am
> > passing two variables by reference but I don't know how to set the
> > variable
> > that I pass to the second form to the value selected in the second form.
> > When I try to set the variable. I get a message from the compiler that
> > states the varaible does not exist in the namespace. My code is below.
> >
> > using System;
> > using System.Drawing;
> > using System.Collections;
> > using System.ComponentModel;
> > using System.Windows.Forms;
> > using System.Data;
> > using System.Data.SqlClient;
> >
> > namespace EnspireUtilities
> > {
> > /// <summary>
> > /// Summary description for Lookup.
> > /// </summary>
> > public class fclsLookup : System.Windows.Forms.Form
> > {
> > private System.Data.SqlClient.SqlDataAdapter sqlDataAdapter1;
> > private System.Data.SqlClient.SqlCommand sqlSelectCommand1;
> > private System.Data.SqlClient.SqlConnection sqlConnection1;
> > private EnspireUtilities.dsLookup dsLookup1;
> > private System.Windows.Forms.DataGrid dataGrid1;
> > private System.Windows.Forms.Button btnLoad;
> > private System.Windows.Forms.TextBox tboxLookupZipCode;
> > private System.Windows.Forms.Label lblLookupParameter;
> > private System.Windows.Forms.Button btnOK;
> > private System.Windows.Forms.Button btnCancel;
> > //private string strZipCode = string.Empty;
> > private System.Windows.Forms.DataGridTableStyle dataGridTableStyle1;
> > private System.Windows.Forms.DataGridTextBoxColumn dataGridTextBoxColumn1;
> > private System.Windows.Forms.DataGridTextBoxColumn dataGridTextBoxColumn2;
> > private System.Windows.Forms.DataGridTextBoxColumn dataGridTextBoxColumn3;
> > private System.Windows.Forms.DataGridTextBoxColumn dataGridTextBoxColumn4;
> > public string strZipCode = String.Empty;
> > public string strZipCodeDtlId = String.Empty;
> >
> >
> > /// <summary>
> > /// Required designer variable.
> > /// </summary>
> > private System.ComponentModel.Container components = null;
> >
> > public fclsLookup(ref string ZipCode, ref string ZipCodeDtlId)
> > {
> > //
> > // Required for Windows Form Designer support
> > //
> > InitializeComponent();
> >
> > //
> > // TODO: Add any constructor code after InitializeComponent call
> > //
> > //tboxLookupZipCode.Text = ZipCode;
> > sqlSelectCommand1.Parameters["@zip"].Value = ZipCode;
> > dsLookup1.Clear();
> > sqlDataAdapter1.Fill(dsLookup1);
> > strZipCode = ZipCode;
> > strZipCodeDtlId = ZipCodeDtlId;
> > tboxLookupZipCode.Text = strZipCode;
> > this.dataGrid1.MouseDown += new
> > System.Windows.Forms.MouseEventHandler(this.dataGrid1_MouseDown);
> >
> > }
> >
> > /// <summary>
> > /// Clean up any resources being used.
> > /// </summary>
> > protected override void Dispose( bool disposing )
> > {
> > if( disposing )
> > {
> > if(components != null)
> > {
> > components.Dispose();
> > }
> > }
> > base.Dispose( disposing );
> > }
> >
> > #region Windows Form Designer generated code
> > /// <summary>
> > /// Required method for Designer support - do not modify
> > /// the contents of this method with the code editor.
> > /// </summary>
> > private void InitializeComponent()
> > {
> > this.sqlDataAdapter1 = new System.Data.SqlClient.SqlDataAdapter();
> > this.sqlSelectCommand1 = new System.Data.SqlClient.SqlCommand();
> > this.sqlConnection1 = new System.Data.SqlClient.SqlConnection();
> > this.dsLookup1 = new EnspireUtilities.dsLookup();
> > this.dataGrid1 = new System.Windows.Forms.DataGrid();
> > this.dataGridTableStyle1 = new System.Windows.Forms.DataGridTableStyle();
> > this.dataGridTextBoxColumn1 = new
> > System.Windows.Forms.DataGridTextBoxColumn();
> > this.dataGridTextBoxColumn2 = new
> > System.Windows.Forms.DataGridTextBoxColumn();
> > this.dataGridTextBoxColumn3 = new
> > System.Windows.Forms.DataGridTextBoxColumn();
> > this.dataGridTextBoxColumn4 = new
> > System.Windows.Forms.DataGridTextBoxColumn();
> > this.btnLoad = new System.Windows.Forms.Button();
> > this.tboxLookupZipCode = new System.Windows.Forms.TextBox();
> > this.lblLookupParameter = new System.Windows.Forms.Label();
> > this.btnOK = new System.Windows.Forms.Button();
> > this.btnCancel = new System.Windows.Forms.Button();
> > ((System.ComponentModel.ISupportInitialize)(this.dsLookup1)).BeginInit();
> > ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
> > this.SuspendLayout();
> > //
> > // sqlDataAdapter1
> > //
> > this.sqlDataAdapter1.SelectCommand = this.sqlSelectCommand1;
> > this.sqlDataAdapter1.TableMappings.AddRange(new
> > System.Data.Common.DataTableMapping[] {
> > new System.Data.Common.DataTableMapping("Table",
> > "p_getZipCodeData", new System.Data.Common.DataColumnMapping[] {
> > new
> > System.Data.Common.DataColumnMapping("zip", "zip"),
> > new
> > System.Data.Common.DataColumnMapping("city", "city"),
> > new
> > System.Data.Common.DataColumnMapping("county", "county"),
> > new
> > System.Data.Common.DataColumnMapping("state", "state"),
> > new
> > System.Data.Common.DataColumnMapping("zip_code_dtl_id",
> > "zip_code_dtl_id")})});
> > //
> > // sqlSelectCommand1
> > //
> > this.sqlSelectCommand1.CommandText = "[p_getZipCodeData]";
> > this.sqlSelectCommand1.CommandType =
> > System.Data.CommandType.StoredProcedure;
> > this.sqlSelectCommand1.Connection = this.sqlConnection1;
> > this.sqlSelectCommand1.Parameters.Add(new
> > System.Data.SqlClient.SqlParameter("@RETURN_VALUE",
> > System.Data.SqlDbType.Int, 4, System.Data.ParameterDirection.ReturnValue,
> > false, ((System.Byte)(0)), ((System.Byte)(0)), "",
> > System.Data.DataRowVersion.Current, null));
> > this.sqlSelectCommand1.Parameters.Add(new
> > System.Data.SqlClient.SqlParameter("@zip", System.Data.SqlDbType.VarChar,
> > 10));
> > //
> > // sqlConnection1
> > //
> > this.sqlConnection1.ConnectionString = "workstation id=CENGENXP2;packet
> > size=4096;user id=sa;data source=cengenxp2;persis" +
> > "t security info=True;initial catalog=src;password=cocacola";
> > //
> > // dsLookup1
> > //
> > this.dsLookup1.DataSetName = "dsLookup";
> > this.dsLookup1.Locale = new System.Globalization.CultureInfo("en-US");
> > //
> > // dataGrid1
> > //
> > this.dataGrid1.DataMember = "p_getZipCodeData";
> > this.dataGrid1.DataSource = this.dsLookup1;
> > this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
> > this.dataGrid1.Location = new System.Drawing.Point(0, 40);
> > this.dataGrid1.Name = "dataGrid1";
> > this.dataGrid1.Size = new System.Drawing.Size(568, 288);
> > this.dataGrid1.TabIndex = 0;
> > this.dataGrid1.TableStyles.AddRange(new
> > System.Windows.Forms.DataGridTableStyle[] {
> > this.dataGridTableStyle1});
> > this.dataGrid1.Navigate += new
> > System.Windows.Forms.NavigateEventHandler(this.dataGrid1_Navigate);
> > //
> > // dataGridTableStyle1
> > //
> > this.dataGridTableStyle1.DataGrid = this.dataGrid1;
> > this.dataGridTableStyle1.GridColumnStyles.AddRange(new
> > System.Windows.Forms.DataGridColumnStyle[] {
> > this.dataGridTextBoxColumn1,
> > this.dataGridTextBoxColumn2,
> > this.dataGridTextBoxColumn3,
> > this.dataGridTextBoxColumn4});
> > this.dataGridTableStyle1.HeaderForeColor =
> > System.Drawing.SystemColors.ControlText;
> > this.dataGridTableStyle1.MappingName = "p_getZipCodeData";
> > //
> > // dataGridTextBoxColumn1
> > //
> > this.dataGridTextBoxColumn1.Format = "";
> > this.dataGridTextBoxColumn1.FormatInfo = null;
> > this.dataGridTextBoxColumn1.HeaderText = "Zip Code";
> > this.dataGridTextBoxColumn1.MappingName = "zip";
> > this.dataGridTextBoxColumn1.Width = 75;
> > //
> > // dataGridTextBoxColumn2
> > //
> > this.dataGridTextBoxColumn2.Format = "";
> > this.dataGridTextBoxColumn2.FormatInfo = null;
> > this.dataGridTextBoxColumn2.HeaderText = "City";
> > this.dataGridTextBoxColumn2.MappingName = "city";
> > this.dataGridTextBoxColumn2.Width = 75;
> > //
> > // dataGridTextBoxColumn3
> > //
> > this.dataGridTextBoxColumn3.Format = "";
> > this.dataGridTextBoxColumn3.FormatInfo = null;
> > this.dataGridTextBoxColumn3.HeaderText = "County";
> > this.dataGridTextBoxColumn3.MappingName = "county";
> > this.dataGridTextBoxColumn3.Width = 75;
> > //
> > // dataGridTextBoxColumn4
> > //
> > this.dataGridTextBoxColumn4.Format = "";
> > this.dataGridTextBoxColumn4.FormatInfo = null;
> > this.dataGridTextBoxColumn4.HeaderText = "State";
> > this.dataGridTextBoxColumn4.MappingName = "state";
> > this.dataGridTextBoxColumn4.Width = 75;
> > //
> > // btnLoad
> > //
> > this.btnLoad.Location = new System.Drawing.Point(472, 8);
> > this.btnLoad.Name = "btnLoad";
> > this.btnLoad.TabIndex = 2;
> > this.btnLoad.Text = "Load";
> > this.btnLoad.Click += new System.EventHandler(this.btnLoad_Click);
> > //
> > // tboxLookupZipCode
> > //
> > this.tboxLookupZipCode.Location = new System.Drawing.Point(136, 8);
> > this.tboxLookupZipCode.Name = "tboxLookupZipCode";
> > this.tboxLookupZipCode.Size = new System.Drawing.Size(200, 20);
> > this.tboxLookupZipCode.TabIndex = 1;
> > this.tboxLookupZipCode.Text = "";
> > //
> > // lblLookupParameter
> > //
> > this.lblLookupParameter.Location = new System.Drawing.Point(24, 8);
> > this.lblLookupParameter.Name = "lblLookupParameter";
> > this.lblLookupParameter.Size = new System.Drawing.Size(100, 20);
> > this.lblLookupParameter.TabIndex = 3;
> > this.lblLookupParameter.Text = "Zip Code";
> > this.lblLookupParameter.TextAlign =
> > System.Drawing.ContentAlignment.MiddleRight;
> > //
> > // btnOK
> > //
> > this.btnOK.DialogResult = System.Windows.Forms.DialogResult.OK;
> > this.btnOK.Location = new System.Drawing.Point(378, 352);
> > this.btnOK.Name = "btnOK";
> > this.btnOK.TabIndex = 3;
> > this.btnOK.Text = "OK";
> > this.btnOK.Click += new System.EventHandler(this.btnOK_Click);
> > //
> > // btnCancel
> > //
> > this.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel;
> > this.btnCancel.Location = new System.Drawing.Point(472, 352);
> > this.btnCancel.Name = "btnCancel";
> > this.btnCancel.TabIndex = 4;
> > this.btnCancel.Text = "Cancel";
> > this.btnCancel.Click += new System.EventHandler(this.btnCancel_Click);
> > //
> > // fclsLookup
> > //
> > this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
> > this.ClientSize = new System.Drawing.Size(568, 390);
> > this.Controls.Add(this.btnCancel);
> > this.Controls.Add(this.btnOK);
> > this.Controls.Add(this.lblLookupParameter);
> > this.Controls.Add(this.tboxLookupZipCode);
> > this.Controls.Add(this.btnLoad);
> > this.Controls.Add(this.dataGrid1);
> > this.Name = "fclsLookup";
> > this.Text = "Lookup";
> > ((System.ComponentModel.ISupportInitialize)(this.dsLookup1)).EndInit();
> > ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
> > this.ResumeLayout(false);
> >
> > }
> > #endregion
> >
> >
> > private void btnLoad_Click(object sender, System.EventArgs e)
> > {
> > sqlSelectCommand1.Parameters["@zip"].Value = tboxLookupZipCode.Text;
> > dsLookup1.Clear();
> > sqlDataAdapter1.Fill(dsLookup1);
> > }
> >
> > private void btnOK_Click(object sender, System.EventArgs e)
> > {
> >
> > Close();
> > }
> >
> > private void btnCancel_Click(object sender, System.EventArgs e)
> > {
> > Close();
> > }
> >
> > private void dataGrid1_Navigate(object sender,
> > System.Windows.Forms.NavigateEventArgs ne)
> > {
> >
> > Close();
> > }
> >
> > protected void dataGrid1_MouseDown(object sender,
> > System.Windows.Forms.MouseEventArgs e)
> > {
> > string strMessage = "TEST";
> >
> > //strMessage = "Row: " + dataGrid1.HitTest(e.X,e.Y).Row.ToString();
> > int x = dataGrid1.HitTest(e.X, e.Y).Row;
> >
> > strZipCode = dataGrid1[x, 0].ToString();
> > strZipCodeDtlId = dataGrid1[x, 3].ToString();
> > MessageBox.Show(strZipCode);
> > MessageBox.Show("I still don't know what I'm doing, but I'm at " +
> > strMessage + ". I need to send back " + strZipCode);
> > }
> >
> > }
> > }
> >
> > "Antti Keskinen" wrote:
> >
> >> Hello !
> >>
> >> There are no stupid questions.
> >>
> >> The forms you define in C# always consist of a class. A single form is a
> >> single class. Thus, your problem comes from the interaction between
> >> classes.
> >> You already knew this, however.
> >>
> >> So, in addition to passing a reference variable to the zip code the user
> >> has
> >> entered (the one which you wish to check), pass in another reference to
> >> the
> >> ACTUAL zip code returned by the lookup form. Now, when the lookup form is
> >> launched, you use the first reference to pass in the zipcode and
> >> initialize
> >> the datagrid to show possible values, and the second reference to pass
> >> back
> >> the value which the user clicked on in the datagrid.
> >>
> >> Here's the most simplest example I can think of. It's written in C++, but
> >> the language syntax is pretty much similar in C#.
> >>
> >> class MyForm1
> >> {
> >> public:
> >> int m_nUsersZipCode;
> >> int m_nDatagridResult;
> >> MyForm2* m_pLookupForm;
> >> };
> >>
> >> class MyForm2
> >> {
> >> public:
> >> DWORD ValidateZipCode(int& nRefSource, int& nRefSelected);
> >> };
> >>
> >> int main(void)
> >> {
> >> MyForm1 form1;
> >> MyForm2 form2;
> >> form1.Show();
> >> }
> >>
> >> // In the ShowLookupForm handler of MyForm1
> >> ..
> >> m_pLookupForm->ValidateZipCode( m_nUsersZipCode,
> >> m_nDatagridResult );
> >> ..
> >>
> >> This would be the most simplistic way to accomplish it. The problem
> >> itself
> >> is not C# related by nature, thus it's quite easy to answer it.
> >>
> >> -Antti Keskinen
> >>
> >> "Johnny" <Johnny@discussions.microsoft.com> wrote in message
> >> news:8E2E1AD0-B607-4671-B2BE-1B8BCB10AF3D@microsoft.com...
> >> > I'm a rookie at C# and OO so please don't laugh! I have a form
> >> > (fclsTaxCalculator) that contains a text box (tboxZipCode) containing a
> >> > zip
> >> > code. The user can enter a zip code in the text box and click a button
> >> > to
> >> > determine whether the zip code is unique. If the zip code is not
> >> > unique,
> >> > another form/dialog is displayed (fclsLookup) - lookup form/dialog.
> >> > The
> >> > zip
> >> > code is passed to the lookup form/dialog by reference. I then load a
> >> > datagrid with the possible matches (i.e. zip, city, county, state,
> >> > zipid).
> >> > When the user clicks the row in the datagrid, I want to pass the zipid
> >> > back
> >> > to the original form/dialog and run a stored procedure. My problem is
> >> > I
> >> > do
> >> > not know how to get the ZipId back to the fclsTaxCalculator
> >> > form/dialog.
> >> > I've search for examples of this and I've not been able to track one
> >> > down -
> >> > please help!!!
> >>
> >>
> >>
>
>
>