[英]The statically inserted items in combobox doubles on button click for more than once
我有一個已插入以下項目的組合框
public void SetOperationDropDown()
{
//ByDefault the selected text in the cmbOperations will be -SELECT OPERATIONS-.
cmbOperations.SelectedItem = "-SELECT OPERATIONS-";
//This is for adding four operations with value in operation dropdown
cmbOperations.Items.Insert(0, "PrimaryKeyTables");
cmbOperations.Items.Insert(1, "NonPrimaryKeyTables");
cmbOperations.Items.Insert(2, "ForeignKeyTables");
cmbOperations.Items.Insert(3, "NonForeignKeyTables");
cmbOperations.Items.Insert(4, "UPPERCASEDTables");
cmbOperations.Items.Insert(5, "lowercasedtables");
}
但是,當用戶單擊按鈕不止一次時,該值就會翻倍,或者該值發生任何不必要的變化。
點擊按鈕是
private void btnConnect_Click(object sender, EventArgs e)
{
//Function call for validating the textboxes entry
ValidateForm();
//Variable to store server address
string localHost = "192.168.10.3";
//Variable to store userId and password of the database
string logInDetails = "gp";
try
{
//Checking for the Valid entries in textboxes if all entries are correct then call functions accordingly
if((txtPassword.Text == logInDetails) && (txtUsername.Text == logInDetails) && (txtHost.Text == localHost))
{
//If connected then give this message to user
lblMessage.Visible = true;
lblMessage.Text = "You are connected to the SQL Server....";
if(lblMessage.Text != string.Empty)
{
//Function call for binding the dropdown with all DB names
BindDBDropDown();
//Function call for binding the operation names in dropdown
SetOperationDropDown();
}
}
else
{
//Else give the error message to user
lblMessage.Text = "Invalid Credentials";
}
}
catch(Exception ex)
{
//All the exceptions are handled and written in the EventLog.
EventLog log = new EventLog("Application");
log.Source = "MFDBAnalyser";
log.WriteEntry(ex.Message);
}
}
誰能幫我嗎?
public void SetOperationDropDown()
{
if(CmbOperations.Items.Count == 0)
{
//ByDefault the selected text in the cmbOperations will be -SELECT OPERATIONS-.
cmbOperations.SelectedItem = "-SELECT OPERATIONS-";
//This is for adding four operations with value in operation dropdown
cmbOperations.Items.Insert(0, "PrimaryKeyTables");
cmbOperations.Items.Insert(1, "NonPrimaryKeyTables");
cmbOperations.Items.Insert(2, "ForeignKeyTables");
cmbOperations.Items.Insert(3, "NonForeignKeyTables");
cmbOperations.Items.Insert(4, "UPPERCASEDTables");
cmbOperations.Items.Insert(5, "lowercasedtables");
}
else
{
int? cbSelectedValue = null;
if(!string.IsNullOrEmpty(cmbOperations.SelectedValue))
cbSelectedValue = convert.toInt32(cmbOperations.SelectedValue);
}
//load your combo again
if(cbSelectedValue != null)
cmbOperations.SelectedValue = cbSelectedValue.ToString();
}
由於我沒有使用VS,所以可能會有一些小的語法錯誤。
僅當頁面的加載不是postback
時才調用SetOperationDropDown()
if (!IsPostBack) {
SetOperationDropDown();
}
用戶單擊時禁用該按鈕,將cmbOperations SelectItem重置為“不執行任何操作”值,並在完成請求處理后重新啟用該按鈕。
這是在WinForms下標記的,因此我認為回發不適用於此處。 在您的btnStartAnalysis_Click
方法中,我看不到它調用SetOperationDropDown
。 嘗試進入DEBUG模式並在SetOperationDropDown
放置一個斷點。 然后單擊您的按鈕,查看是否達到了斷點。 如果是這樣,則請參考您的堆棧跟蹤以查看從何處SetOperationDropDown
。
如果WinForms標記不正確,而您實際上正在使用WebForms / ASP.NET,請執行Stefanvds和Marcel的建議。 但是我認為弄清楚SetOperationDropDown
從哪里被錯誤地調用很重要。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.