Not sure whether it is a flaw in .NET or not, but:
If a user empties a combo box (i.e. wants to blank out the value) the selected value does not revert to null, Instead it keeps the last valid selected value, so when you save with a blank combobox it goes back to the original value.
One workaround to ensure that Value is NULL is to first choose an option from the dropdown click save, and close. Open it again, delete it and then save. Then it will save into the database with the null value.
Proposed Solutions:
I can either fix this somehow, not sure (hence asking for help here) and have it in a way that when use empties the text in the combobox (NOTE: Combobx is not a dropdown list rather just a dropwdown) and saves, it will see the blank text and save the value in the database as null.
Other option is that I can have it as a dropdown list with the BLANK /NULL as option so that when it is clicked it will save NULL as value.
I am new to this, hence will need help.
It does use databinding, hence not sure how to add the null value, also I do not want to add the null option to that table as it contains names and usernames for people. So if there is no user selected it should save as NULL.
Bits and pieces of this code is the following:
private void InitializeComponent() {
this.components = new System.ComponentModel.Container();
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(DealsRibbonForm));
System.Windows.Forms.DataGridViewCellStyle dataGridViewCellStyle1 = new System.Windows.Forms.DataGridViewCellStyle();
System.Windows.Forms.DataGridViewCellStyle dataGridViewCellStyle2 = new System.Windows.Forms.DataGridViewCellStyle();
System.Windows.Forms.DataGridViewCellStyle dataGridViewCellStyle3 = new System.Windows.Forms.DataGridViewCellStyle();
this.pnlCSRs = new System.Windows.Forms.Panel(); this.cmbSecCSR = new System.Windows.Forms.ComboBox();
this.csrBindingSource2 = new System.Windows.Forms.BindingSource(this.components);
this.cmbCameraRC = new System.Windows.Forms.ComboBox();
this.csrBindingSource3 = new System.Windows.Forms.BindingSource(this.components);
// pnlCSRs
//
this.pnlCSRs.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
this.pnlCSRs.Controls.Add(this.cmbSecCSR); // cmbSecCSR // this.cmbSecCSR.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.SuggestAppend; this.cmbSecCSR.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems; this.cmbSecCSR.DataSource = this.csrBindingSource2; this.cmbSecCSR.DisplayMember = "Name"; this.cmbSecCSR.FormattingEnabled = true; this.cmbSecCSR.Location = new System.Drawing.Point(112, 26); this.cmbSecCSR.Margin = new System.Windows.Forms.Padding(0); this.cmbSecCSR.Name = "cmbSecCSR"; this.cmbSecCSR.Size = new System.Drawing.Size(184, 21); this.cmbSecCSR.TabIndex = 2; this.cmbSecCSR.ValueMember = "Username"; this.cmbSecCSR.TextChanged += new System.EventHandler(this.comboBox_TextChanged); this.cmbSecCSR.Enter += new System.EventHandler(this.cmbBox_Entered); // // csrBindingSource2 // this.csrBindingSource2.DataMember = "CSR"; this.csrBindingSource2.DataSource = this.productionDS;
The two Event Handles associated with cmbSecCSR are the following:
private void comboBox_TextChanged(object sender, EventArgs e)
{
ComboBox cmbx = (ComboBox)sender;
if (cmbx.Equals(cmbCamSupplier))
{
}
else if (cmbx.Equals(cmbLGSupplier))
{
}
if (cmbx.Text.Length > 0) return;
cmbx.SelectedValue = "";
cmbx.SelectedIndex = -1;
}
private void cmbBox_Entered(object sender, EventArgs e)
{
ComboBox cmb = (ComboBox)sender;
String txt = cmb.Text;
if (cmb.Name.Contains("CSR"))
{
if (cmb != null)
{
((BindingSource)cmb.DataSource).Filter = (cmbOffice.SelectedIndex > -1 ? "Office = '" + cmbOffice.SelectedValue + "' AND " : "") + "IsCSR=1 AND Status=1";
cmb.Text = txt;
}
}
else if (cmb.Name.Contains("RC"))
{
int department = 0;
if (cmb != null)
{
if (cmb.Name.Contains("Camera"))
department = 2;
else if (cmb.Name.Contains("LG"))
department = 3;
else if (cmb.Name.Contains("Power"))
department = 4;
((BindingSource)cmb.DataSource).Filter = (cmbOffice.SelectedIndex > -1 ? "Office = '" + cmbOffice.SelectedValue + "' AND " : "") + "IsCSR=0 AND Status=1 AND (Department = " + department + " OR Department is null OR Department = 0)";
cmb.Text = txt;
}
}
}Please HELP, I have been struggling with this for a while now.