[英]Is it possible to pass textboxes as a parameter?
我試圖將2個文本框的名稱傳遞給方法,以便它編輯其中的文本。 我嘗試過在線查找示例,但只能找到嘗試傳遞文本框文本的人。
我嘗試通過在方法構造函數中聲明文本框來傳遞它。
MethodName(string text, tb_1, tb_2);
private void MethodName(string str, TextBox tb_name, TextBox tb_allergen)
{
string ingredientName = "";
string ingredientAllergen = "";
//code to change strings//
tb_name.Text = ingredientName;
tb_allergen.Text = ingredientAllergen;
}
運行代碼后,我希望將文本框文本更改為適當的值,相反,會在調用中收到有關文本框的此錯誤。
“ mscorlib.dll中發生了'System.InvalidCastException'類型的未處理的異常
其他信息:無法將類型為“ System.Windows.Forms.TextBox”的對象轉換為類型為“ System.IConvertible”的對象”
如果有一個簡單的解決方法,對此非常抱歉,但是請向我指出正確的方向。 提前致謝。
實碼
ingredientDBAccess ingredientDBA = new ingredientDBAccess(db);
populateBoxesWithIngredientResults( ingredientDBA.getIngredientsFromID(Convert.ToInt32(tb_viewIngredient1)), tb_viewIngredient1, tb_viewAllergen1);
private void populateBoxesWithIngredientResults(List<ingredient> ingredientList, TextBox tb_name, TextBox tb_allergen)
{
string ingredientName = "";
string ingredientAllergen = "";
foreach (ingredient ingredient in ingredientList)
{
string name = Convert.ToString(ingredient.IngredientName);
ingredientName = name;
string allergen = "N/A";
switch (ingredient.AllergenID)
{
case 0:
allergen = "N/A";
break;
case 1:
allergen = "Nut";
break;
case 2:
allergen = "Gluten";
break;
case 3:
allergen = "Dairy";
break;
case 4:
allergen = "Egg";
break;
}
ingredientAllergen = allergen;
}
tb_name.Text = ingredientName;
tb_allergen.Text = ingredientAllergen;
}
對的,這是可能的:
void MyMethod(string str, TextBox txt)
{
txt.Text = str + " some text from the method itself";
}
您甚至可以返回TextBox:
TextBox MyFunc(string str)
{
TextBox txt = new TextBox();
txt.Text = str;
return txt;
}
您正在嘗試將TextBox轉換為Int32:無法解析為Int32的Convert.ToInt32(tb_viewIngredient1)
。 您可以將其文本轉換為int32(如果它具有數字值並且可以解析),例如:
int.Parse(tb_viewIngredient1.Text)
要么
Conver.ToInt32(tb_viewIngredient1.Text)
問題是在兩個地方
MethodName(
字符串
theStringVariable,tb_1,tb_2);
私人void MethodName(string theStringVariable ,TextBox tb_name,TextBox tb_allergen){
Convert.ToInt32(tb_viewIngredient1)
將引發異常,因為您正嘗試將TextBox
控件轉換為int
。 而是嘗試將TextBox
的Text
屬性傳遞給方法:
Convert.ToInt32(tb_viewIngredient1.Text)
問題出在(Convert.ToInt32(tb_viewIngredient1)
,您必須將其轉換為:
(Convert.ToInt32(tb_viewIngredient1.Text)
我在這里看到三個不同的選擇。 根據您的需求,這些方法甚至比固定代碼更好。 它們都解決了兩點:
ingredientList
,但文本框將只從列表中最后一項保留數據。 要么只看最后一個項目(不需要循環),要么使用列表中的所有項目(即:創建csv字符串)。 循環很浪費,並且使代碼復雜化。 。
private void populateBoxesWithIngredientResults(IEnumerable<ingredient> ingredientList, TextBox tb_name, TextBox tb_allergen)
{
string nameDelimiter = "";
string allergenDelimiter = "";
string ingredients = "";
string allergens = "";
var allergenTable = {"N/A", "Nut", "Gluten", "Dairy", "Egg"};
foreach (ingredient ingredient in ingredientList)
{
//Is Convert.ToString() really needed here?
// I feel like ingredient.IngredientName is ALREADY A STRING
ingredients += delimiter + Convert.ToString(ingredient.IngredientName);
nameDelimiter = ",";
if (ingredient.AllergenID > 0 && ingredient.AllergenID < allergenTable.Length)
{
allergens += allergenDelimiter + allergenTable[ingredient.AllergenID];
allergenDelimiter = ",";
}
}
if (allergens == "") allergens = "N/A";
tb_name.Text = ingredients;
tb_allergen.Text = allergens;
}
要么
private void populateBoxesWithIngredientResults(IEnumerable<ingredient> ingredientList, TextBox tb_name, TextBox tb_allergen)
{
tb_name.Text = string.Join(",", ingredientList.Select(i => i.IngredientName));
var allergenTable = {"N/A", "Nut", "Gluten", "Dairy", "Egg"};
var allergens = ingredientList.
Select(i => (i.AllergenID > 0 && i.AllergenID < allergenTable.Length)? allergenTable[i.AllergenID]):"").
Where(i => i.Length > 0);
var result = string.Join(",", allergens);
if (string.IsNullOrEmpty(result)) result = "N/A";
tb_allergen.Text = result;
}
要么
private void populateBoxesWithIngredientResults(List<ingredient> ingredientList, TextBox tb_name, TextBox tb_allergen)
{
if (ingredientList.Length == 0)
{
tb_name.Text = "";
tb_allergen.Text = "";
}
var allergenTable = {"N/A", "Nut", "Gluten", "Dairy", "Egg"};
var ingredient = ingredientList[ingredientList.Count - 1];
tb_name.Text = ingredient.IngredientName;
if (ingredient.AllergenID >= 0 && ingredient.AllergenID < allergenTable.Length)
{
tb_allergen.Text = allergenTable[ingredient.AllergenID];
}
else
{
tb_allergen.Text = "N/A";
}
}
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