DevExpress 如何向lookUpEditor中添加新值

How to Use the ProcessNewValue Event of a LookUp Editor

Tags:

• .NET,
• XtraEditors Library

Alex Klim (DevExpress)16 years ago

• How to Use the ProcessNewValue Event of a LookUp Editor

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1 Solution

Alex Klim (DevExpress)16 years ago

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The LookUp editor allows a user to enter values which cannot be found in the lookup list. A programmer should handle this situation, otherwise a new value is lost. The LookUp editor provides a ProcessNewValue event for this.

First of all, you should set the SearchMode property to OnlyInPopup and TextEditStyle to Standard to enable free text entry.

There are two common approaches for handling the ProcessNewValue event:
1. Immediately insert the new record in the lookup table and generate a new ID for it.
2. Display a dialog, where a user can set values for a new data row.

Below are two code snippets which demonstrate the implementation of these approaches.

[C#]Open in popup window

// solution 1 

private void LookUpEdit1_ProcessNewValue(object sender, DevExpress.XtraEditors.Controls.ProcessNewValueEventArgs e) {

   DataRow Row;

   RepositoryItemLookUpEdit Edit;

   Edit = ((LookUpEdit)sender).Properties;



   if(e.DisplayValue == null || Edit.NullText.Equals(e.DisplayValue) || string.Empty.Equals(e.DisplayValue))

       return;



   Row = LookupTable.NewRow();

   Row["Name"] = e.DisplayValue;

   LookupTable.Rows.Add(Row);

   

   e.Handled = true;

}



// solution 2 

private void LookUpEdit1_ProcessNewValue(object sender, DevExpress.XtraEditors.Controls.ProcessNewValueEventArgs e) {

   DataRow Row;

   RepositoryItemLookUpEdit Edit;

   Edit = ((LookUpEdit)sender).Properties;



   if(e.DisplayValue == null || Edit.NullText.Equals(e.DisplayValue) || string.Empty.Equals(e.DisplayValue))

       return;

       

   using(Form2 f = new Form2()) {

       f.ItemID = "(Auto Number)";

       f.ItemName = e.DisplayValue.ToString();

       if(f.ShowDialog(this) == System.Windows.Forms.DialogResult.OK) {

           e.DisplayValue = f.ItemName;

           Row = LookupTable.NewRow();

           Row["Name"] = f.ItemName;

           LookupTable.Rows.Add(Row);

       }

   }

       

   e.Handled = true;

}